Add comprehensive documentation for FlowSight project

- Introduced AGENT-SPECS.md detailing the specifications for seven agents including their inputs, processing steps, and outputs.
- Created API-REFERENCE.md outlining the Sectors API v2 endpoints, parameters, costs, and usage.
- Developed API.md to specify backend routes, request/response structures, and error handling.
- Established ARCHITECTURE.md to describe the project layout, conventions, scheduler, and citation pipeline.
- Added DATA-MODEL.md to define the database schema, tables, and seed strategy.
- Compiled PLAN.md to outline the project concept, problem statement, unique features, and implementation timeline.
- Created README.md as an index for documentation with links to all relevant files.
- Documented ROUTINES.md detailing the seven automated routines, their schedules, inputs, detection logic, and delivery formats.
- Introduced TECH-STACK.md to specify the technology choices and rationale for both backend and frontend components.

docs/TECH-STACK.md

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+# Tech stack
+
+Pinned versions. Change here before code. CI enforces the gates at the bottom.
+
+## Backend — `backend/` (Go 1.23)
+
+| Piece | Choice | Why |
+|---|---|---|
+| Runtime | Go 1.23 | Single binary, fast cold start on demo machines, `net/http` routing mature since 1.22 |
+| Router | chi v5 | Thin router over stdlib mux (middleware, route groups); no framework lock-in |
+| HTTP client | stdlib `net/http` + tuned `Transport` | One shared client for all Sectors calls (pooling, per-endpoint timeouts) |
+| Validation | go-playground/validator v10 | Request struct tags = kontrak docs/API.md; gagal validasi → 422 |
+| DB | `database/sql` + modernc.org/sqlite (pure Go) | Nol CGO — `mattn/go-sqlite3` butuh gcc dan gagal di mesin juri tanpa toolchain; schema Postgres-compatible, migrasi SQL polos bernomor, tanpa ORM |
+| Cache | go-redis v9; in-memory TTL fallback bila `REDIS_URL` kosong | Cache registry/taxonomy (TTL 24 jam); demo tetap jalan tanpa Redis |
+| Scheduler | robfig/cron v3 | Cron per routine + interval ingestion dalam satu proses |
+| LLM | Plain HTTPS ke endpoint OpenAI-compatible (`LLM_BASE_URL`) | Function calling untuk synthesis/report/briefing; `LLM_MODEL_TRIAGE` murah + `LLM_MODEL_SYNTH` kuat, override lewat env |
+| PDF export | gofpdf (jung-kurt fork) | Pure Go, tanpa system deps |
+| Config | env via `os.Getenv` + `godotenv` untuk dev | Semua secret dari env; contoh di `.env.example` |
+| Test | `go test` + `httptest` (mock upstream Sectors) | Agent/rule/budget tests atas fixture JSON bentuk API asli |
+| Lint/type | `gofmt -l` + `go vet ./...` (+ golangci-lint bila tersedia) | Compiler sudah strict; vet menangkap yang penting |
+
+## Frontend — `web/` (SolidJS + StyleX)
+
+| Piece | Choice | Why |
+|---|---|---|
+| Framework | SolidJS 1.9 + Vite 6 + TypeScript 5.6 | Fine-grained reactivity — ideal untuk live feed/SSE tanpa re-render tree; bundle kecil untuk demo cepat |
+| Styling | StyleX (@stylexjs/stylex + @stylexjs/vite-plugin) | Atomic CSS deterministic, typed via TS, tanpa runtime; ganti Tailwind sepenuhnya |
+| Charts | Chart.js 4 via solid-chartjs | Wrapper Solid resmi untuk flow/series; Recharts React-only jadi tidak dipakai |
+| Data fetch | `fetch` + typed client (`lib/api.ts`) + `EventSource` untuk SSE | Backend satu-satunya sumber kebenaran; web tidak pernah manggil Sectors langsung |
+| Test/gate | `tsc --noEmit` + `vite build` | Cukup untuk hackathon; tanpa e2e framework |
+
+## Package / runtime management
+
+| Piece | Choice | Why |
+|---|---|---|
+| Go deps | Go modules (`go.mod`, vendoring opsional via `go mod vendor`) | Build reproducible; `go build ./...` satu perintah |
+| JS deps | pnpm 9 + `pnpm-lock.yaml` | Install deterministik; fallback `npm` jika pnpm tidak ada |
+| Env | `.env` (tidak di-commit) — `SECTORS_API_KEY`, `LLM_API_KEY`, `LLM_BASE_URL`, `LLM_MODEL_SYNTH`, `LLM_MODEL_TRIAGE`, `TELEGRAM_BOT_TOKEN`, `DISCORD_WEBHOOK_URL`, `REDIS_URL` | Semua secret dari env; contoh di `.env.example` |
+| Procfile dev | dua proses: `go run ./cmd/server` (atau `air` untuk reload) + `vite dev` (+ redis opsional) | Demo tetap jalan tanpa Redis |
+
+## Alternatives declined
+
+- **Python/FastAPI** — startup + packaging demo lebih rapuh (venv, pip) dibanding satu binary Go; konkurensi agent paralel setara via goroutine.
+- **Next.js/React** — overhead framework + re-render model untuk dashboard live; Solid memberi update granular dengan bundle lebih kecil.
+- **Tailwind** — diganti StyleX: atomic, typed, nol runtime, tanpa scanning step.
+- **Recharts** — React-only; Chart.js via solid-chartjs menutup kebutuhan chart di Solid.
+- **mattn/go-sqlite3** — butuh CGO/gcc; modernc pure-Go selalu bisa build.
+- **GORM / sqlc / Alembic-style migrator** — overhead untuk 13 tabel; SQL polos + skrip bernomor cukup dan mudah diaudit juri.
+- **Celery / job queue eksternal** — butuh broker; cron in-process cukup untuk siklus 30 menit.
+- **WebSocket** — push satu arah saja (agents/alerts/activity); SSE lebih simpel + auto-reconnect.
+- **tRPC / GraphQL** — REST + JSON typed tanpa layer tambahan.
+- **MongoDB** — data relasional time-series (ticker × date); SQLite + indeks tepat lebih cepat dibangun.
+
+## CI gates (per commit)
+
+1. `gofmt -l backend/` kosong + `go vet ./...` bersih
+2. `go test ./...` (termasuk budget test: kredit per siklus ≤ cap pada fixture)
+3. `tsc --noEmit` + `vite build` di `web/`
+4. Larangan: tidak ada HTTP call ke `api.sectors.app` di luar `backend/sectors/`;
+   tidak ada angka user-visible tanpa citation (review checklist, bukan linter).