Fill gaps in shared pattern contracts

- modal-workflows: full state machine, htmx pattern, validation rules
- go-api: REST conventions, URL naming, status codes, error format, list response
- import-export: streaming export 3-layer architecture with Go example
- CLAUDE.template.md: updated to include modals and REST API references

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

kit/ai/claude/CLAUDE.template.md

@@ -1,57 +1,55 @@
 # {{ .project_name }} — Instructions for Claude
 
-Read and follow the project Bible before making any changes:
+## Shared Engineering Rules
+Read `bible/` — shared rules for all projects (CSV, logging, DB, tables, background tasks, code style).
+Start with `bible/kit/patterns/` for specific contracts.
 
-**[`bible/README.md`](bible/README.md)**
-
-The Bible is the single source of truth for architecture, data models, API contracts, and UI
-pattern conventions. Every significant architectural decision must be recorded in the Bible
-decision log before or alongside the code change.
+## Project Architecture
+Read `bible-local/` — project-specific architecture.
+Every architectural decision specific to this project must be recorded in `bible-local/`.
 
 ---
 
-## Shared Engineering Rules
+## Quick Reference (full contracts in `bible/kit/patterns/`)
 
-The following rules apply to ALL changes in this project.
-They are maintained centrally in `tools/ui-design-code/kit/patterns/`.
+### Go Code Style (`go-code-style/contract.md`)
+- Handler → Service → Repository. No SQL in handlers, no HTTP writes in services.
+- Errors: `fmt.Errorf("context: %w", err)`. Never discard with `_`.
+- `gofmt` before every commit.
+- Thresholds and status logic on the server — UI only reflects what server returns.
 
-### Go Code Style
-See [`tools/ui-design-code/kit/patterns/go-code-style/contract.md`](tools/ui-design-code/kit/patterns/go-code-style/contract.md)
-- Handler → Service → Repository layering
-- Error wrapping with `fmt.Errorf("...: %w", err)`
-- Startup sequence: connect DB → migrate → start server
-- Business logic and status thresholds live on the server, not in JS
+### Logging (`go-logging/contract.md`)
+- `slog`, stdout/stderr only. Never `console.log` as substitute for server logging.
+- Always log: startup, task start/finish/error, export row counts, ingest results, any 500.
 
-### Logging
-See [`tools/ui-design-code/kit/patterns/go-logging/contract.md`](tools/ui-design-code/kit/patterns/go-logging/contract.md)
-- Use `slog`, log to binary stdout/stderr only
-- Never use `console.log` as a substitute for server-side logging
-- Always log: startup, background task start/finish/error, export row counts, ingest results
+### Database (`go-database/contract.md`)
+- **CRITICAL**: never run SQL on the same tx while iterating a cursor. Two-phase: read all → close → write.
+- Soft delete via `is_active = false`.
+- Fail-fast DB ping before starting HTTP server.
+- No N+1: use JOINs or batch `WHERE id IN (...)`.
+- GORM: `gorm:"-"` = fully ignored; `gorm:"-:migration"` = skip migration only.
 
-### Database
-See [`tools/ui-design-code/kit/patterns/go-database/contract.md`](tools/ui-design-code/kit/patterns/go-database/contract.md)
-- **CRITICAL**: never execute SQL on the same tx while iterating a cursor — two-phase only
-- Soft delete via `is_active = false`, not physical deletes
-- Fail-fast DB check before starting the HTTP server
-- No N+1 queries: use JOINs or batch `IN` queries
+### REST API (`go-api/contract.md`)
+- Plural nouns: `/api/assets`, `/api/components`.
+- Never `200 OK` for errors — use `422` for validation, `404`, `500`.
+- Error body: `{"error": "message", "fields": {"field": "reason"}}`.
+- List response always includes `total_count`, `page`, `per_page`, `total_pages`.
+- `/health` and `/api/db-status` required in every app.
 
-### Background Tasks
-See [`tools/ui-design-code/kit/patterns/go-background-tasks/contract.md`](tools/ui-design-code/kit/patterns/go-background-tasks/contract.md)
-- All slow operations: POST → task_id → client polls `/api/tasks/:id`
-- No SSE — polling only
-- Return `202 Accepted` when task is created
+### Background Tasks (`go-background-tasks/contract.md`)
+- Slow ops (>300ms): POST → `{task_id}` → client polls `/api/tasks/:id`.
+- No SSE. Polling only. Return `202 Accepted`.
 
-### Tables, Filtering, Pagination
-See [`tools/ui-design-code/kit/patterns/table-management/contract.md`](tools/ui-design-code/kit/patterns/table-management/contract.md)
-- Server-side filtering and pagination only
-- Filter state in URL query params; applying a filter resets to page 1
-- Response must include `total_count`, `page`, `per_page`, `total_pages`
-- Display format: "51–100 из 342"
+### Tables, Filtering, Pagination (`table-management/contract.md`)
+- Server-side only. Filter state in URL params. Filter resets to page 1.
+- Display: "51–100 из 342".
 
-### CSV Export
-See [`tools/ui-design-code/kit/patterns/import-export/contract.md`](tools/ui-design-code/kit/patterns/import-export/contract.md)
-- UTF-8 BOM required (`\xEF\xBB\xBF`)
-- Semicolon delimiter (`;`), not comma
-- Decimal separator: comma (`1 234,56`), not period
-- Dates as `DD.MM.YYYY`
-- `csv.Writer` with `Comma = ';'`
+### Modals (`modal-workflows/contract.md`)
+- States: open → submitting → success | error.
+- Destructive actions require confirmation modal naming the target.
+- Never close on error. Use `422` for validation errors in htmx flows.
+
+### CSV Export (`import-export/contract.md`)
+- BOM: `\xEF\xBB\xBF`. Delimiter: `;`. Decimal: `,` (`1 234,56`). Dates: `DD.MM.YYYY`.
+- Stream via callback — never load all rows into memory.
+- Always call `w.Flush()` after the loop.

kit/patterns/go-api/contract.md

@@ -0,0 +1,91 @@
+# Contract: REST API Conventions (Go Web Applications)
+
+## URL Naming
+
+- Resources are plural nouns: `/api/assets`, `/api/components`, `/api/pricelists`.
+- Nested resources use parent path: `/api/assets/:id/components`.
+- Actions that are not CRUD use a verb suffix: `/api/pricelists/:id/export-csv`,
+  `/api/tasks/:id/cancel`, `/api/sync/push`.
+- No verbs in resource paths: use `/api/assets` + DELETE, not `/api/delete-asset`.
+
+## HTTP Methods and Status Codes
+
+| Operation | Method | Success | Notes |
+|-----------|--------|---------|-------|
+| List | GET | 200 | |
+| Get one | GET | 200 / 404 | |
+| Create | POST | 201 | Return created resource |
+| Update | PUT / PATCH | 200 | Return updated resource |
+| Delete / Archive | DELETE | 200 or 204 | |
+| Async action | POST | 202 | Return `{task_id}` |
+| Validation error | POST/PUT | 422 | Return field errors |
+| Server error | any | 500 | Log full error server-side |
+| Not found | any | 404 | |
+| Unauthorized | any | 401 | |
+
+- Never return `200 OK` for validation errors — use `422 Unprocessable Entity`.
+- Never return `200 OK` with `{"error": "..."}` in the body — use the correct status code.
+
+## Error Response Format
+
+All non-2xx responses return a consistent JSON body:
+
+```json
+{
+  "error": "human-readable message",
+  "fields": {
+    "serial_number": "Serial number is required",
+    "price": "Must be greater than 0"
+  }
+}
+```
+
+- `error` — always present, describes what went wrong.
+- `fields` — optional, present only for validation errors (422). Keys match form field names.
+- Never expose raw Go error strings, stack traces, or SQL errors to the client.
+
+## List Response Format
+
+```json
+{
+  "items": [...],
+  "total_count": 342,
+  "page": 2,
+  "per_page": 50,
+  "total_pages": 7
+}
+```
+
+- Always include pagination metadata even if the client did not request it.
+- `items` is always an array — never `null`, use `[]` for empty.
+
+## Request Conventions
+
+- Accept `application/json` for API endpoints.
+- HTML form submissions (htmx) use `application/x-www-form-urlencoded` or `multipart/form-data`.
+- File uploads use `multipart/form-data`.
+- Query parameters for filtering and pagination: `?page=1&per_page=50&search=abc&status=active`.
+
+## Health and Utility Endpoints
+
+Every application must expose:
+
+```
+GET /health       → 200 {"status": "ok"}
+GET /api/db-status → 200 {"ok": true} or 500 {"ok": false, "error": "..."}
+```
+
+- `/health` must respond even if DB is down (for load balancer probes).
+- `/api/db-status` checks the actual DB connection and returns its state.
+
+## Async Actions
+
+For long-running operations return immediately with a task reference:
+
+```
+POST /api/pricelists/create → 202 {"task_id": "abc123"}
+GET  /api/tasks/abc123      → 200 {"status": "running", "progress": 42, "message": "Processing..."}
+GET  /api/tasks/abc123      → 200 {"status": "success", "result": {...}}
+```
+
+See `go-background-tasks/contract.md` for full task contract.

kit/patterns/import-export/contract.md

@@ -71,8 +71,53 @@ fmt.Sprintf("%.2f", price)
 - Escape embedded double-quotes by doubling them: `""`.
 - Use `encoding/csv` with `csv.Writer` and set `csv.Writer.Comma = ';'`; it handles quoting automatically.
 
+## Streaming Export Architecture (Go)
+
+For exports with potentially large row counts use a 3-layer streaming pattern.
+Never load all rows into memory before writing — stream directly to the response writer.
+
+```
+Handler → sets HTTP headers + writes BOM → calls Service
+Service → delegates to Repository with a row callback
+Repository → queries in batches → calls callback per row
+Handler/Service → csv.Writer.Flush() after all rows
+```
+
+```go
+// Handler
+func ExportCSV(c *gin.Context) {
+    c.Header("Content-Type", "text/csv; charset=utf-8")
+    c.Header("Content-Disposition", `attachment; filename="export.csv"`)
+    c.Writer.Write([]byte{0xEF, 0xBB, 0xBF}) // BOM
+
+    w := csv.NewWriter(c.Writer)
+    w.Comma = ';'
+    w.Write([]string{"ID", "Name", "Price"}) // header row
+
+    err := svc.StreamRows(ctx, filters, func(row Row) error {
+        return w.Write([]string{row.ID, row.Name, formatPrice(row.Price)})
+    })
+    w.Flush()
+    if err != nil {
+        // headers already sent — log only, cannot change status
+        slog.Error("csv export failed mid-stream", "err", err)
+    }
+}
+
+// Repository — batch fetch with callback
+func (r *Repo) StreamRows(ctx, filters, fn func(Row) error) error {
+    rows, err := r.db.QueryContext(ctx, query, args...)
+    // ... scan and call fn(row) for each row
+}
+```
+
+- Use `JOIN` in the repository query to avoid N+1 per row.
+- Batch size is optional; streaming row-by-row is fine for most datasets.
+- Always call `w.Flush()` after the loop — `csv.Writer` buffers internally.
+
 ## Error Handling
 
 - Import errors should map to clear user-facing messages.
-- Export errors after streaming starts must degrade gracefully (human-readable fallback).
+- Export errors after streaming starts must be logged server-side only — HTTP headers are already
+  sent and the status code cannot be changed mid-stream.
 

kit/patterns/modal-workflows/contract.md

@@ -1,9 +1,56 @@
 # Contract: Modal Workflows
 
-## Shared Rules
+## State Machine
 
-- Destructive actions require explicit confirmation.
-- Validation and backend errors are rendered in human-readable form.
-- UI state transitions are explicit (`open` / `submit` / `success` / `error` / `cancel`).
-- API contracts and UI copy should be documented in the host project's Bible.
+Every modal has exactly these states:
 
+```
+closed → open → submitting → success | error
+                           ↓
+                        cancel → closed
+```
+
+- `open`: form visible, submit enabled.
+- `submitting`: form disabled, spinner on submit button, no double-submit possible.
+- `success`: close modal, show toast, refresh affected data.
+- `error`: stay open, show error message inline, re-enable form.
+- `cancel`: close without changes, no confirmation needed unless form is dirty.
+
+## Rules
+
+- Destructive actions (delete, archive, bulk remove) require a separate confirmation modal — not
+  just a disabled button. Confirmation modal must name the target: "Delete component ABC-123?"
+- Never close a modal automatically on error — keep it open so the user can retry or copy the error.
+- Submit button text must describe the action: "Save", "Delete", "Archive" — not "OK" or "Confirm".
+- Modal title must match the action: "Edit Component", "Delete Asset" — not generic "Modal".
+- Escape key and clicking the backdrop close the modal (unless in `submitting` state).
+
+## Validation
+
+- Validate on submit server-side. Client-side validation is optional progressive enhancement only.
+- Show field-level errors inline below each field.
+- Show a form-level error summary at the top if multiple fields fail.
+- Error messages must be human-readable and action-oriented: "Serial number is required" — not
+  "serial_number: cannot be null".
+
+## htmx Pattern (server-rendered modals)
+
+```
+POST /api/entity        → 200 OK + HX-Trigger: "entitySaved"   (success)
+                        → 422 Unprocessable + partial HTML      (validation error, re-render form)
+                        → 500 + error message                   (server error)
+```
+
+- On success: server sends `HX-Trigger` header, JS listener closes modal and refreshes list.
+- On validation error: server re-renders the form partial with inline errors (422).
+- On server error: show generic error toast, log full error server-side.
+- Do not use `200 OK` for validation errors — use `422` so htmx can differentiate.
+
+## Multi-Step Modals
+
+Use only when the workflow genuinely requires staged input (e.g. import preview → confirm).
+
+- Show a step indicator (Step 1 of 3).
+- Back button must restore previous step values.
+- Final confirm step must summarise what will happen before the destructive/irreversible action.
+- Single-step edits must NOT be split into multi-step without good reason.