emileriksenkeev turns Mike into a Philippine legal-practice operating system

Rebrand the Mike OSS upstream to "Syd OS" for RX Ventures' internal legal
deployment. Changes preserve upstream LICENSE (AGPL-3.0) and add NOTICE.md
crediting the original project.

- chatTools.ts SYSTEM_PROMPT rewritten as "You are Syd" with the Philippine
  legal context block from the Syd setup spec §7.2 (PH regulators, contract
  types, drafting defaults, citation rules, prohibitions).
- Frontend brand swap across layout metadata, login, signup, sidebar,
  logo, global error page, workflow list badge, support page, and analysis
  prompt placeholders.
- layout.tsx: title/OG/twitter now Syd OS at legal.rxventures.co;
  added robots: noindex/nofollow.
- signup/page.tsx: replaced demo-service notice with "self-signup disabled"
  text (Supabase signups are off in the Syd OS deployment).
- schema.sql: added metadata jsonb columns on documents and workflows
  (default {"source_system":"syd_os"}). Reserved per Syd spec §8 for v1.1
  Capital integration (cap_event_id binding).
- New stub: backend/src/routes/integrations/capital.ts mounts at
  /api/integrations/capital/webhook and returns 501. Reserves the URL path
  for the v1.1 Rx Capital wire-up.

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

Add the 5 pre-loaded workflows and 5 document template skeletons per Syd
setup spec §7.3 and §7.4.

- backend/seed/01_workflows.sql: idempotent INSERTs for 5 system workflows
  (Review Supplier/Distributor Agreement PH, PH Data Privacy Act Compliance
  Review, Draft Mutual NDA PH, Contract Summary, Review Incoming SAFE /
  Term Sheet SEA). Visible to all users via is_system = true; upserts on
  title.
- backend/seed/templates/: 5 markdown template drafts (Doctor Independent
  Contractor PH, Distributor/Supplier PH, Mutual NDA PH, Patient Telehealth
  Consent PH, Employment/Contractor PH). Each carries the "AI-assisted draft
  - counsel review required before execution" warning at the top.
- backend/seed/README.md: documents the apply order (schema.sql first,
  then seed) and notes that templates are uploaded via the app UI to a
  "Syd Templates" project rather than inserted directly via SQL.

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

The five PH workflows (spec §7.3) were seeded as is_system=true rows in
backend/seed/01_workflows.sql, but nothing in the upstream Mike app reads
is_system=true - the workflow list route returns only own+shared rows, and
the chat workflow store reads the hardcoded builtin arrays. The seeded rows
were therefore invisible, while the generic upstream built-ins (CP checklist,
credit agreement, LPA, England & Wales lease, e-discovery, etc.) still showed.

- Replace both built-in registries with the five PH workflows, matching IDs:
    backend/src/lib/builtinWorkflows.ts (chat-assistant tool store)
    frontend/src/app/components/workflows/builtinWorkflows.ts (Built-in tab)
  Removes the off-jurisdiction / off-domain generic workflows. The tabular
  review feature stays available for user-created workflows; PH tabular
  templates can be added later.
- Mark backend/seed/01_workflows.sql SUPERSEDED (running it would insert
  invisible duplicate rows) and update seed/README.md accordingly.
- README.md: rebrand header Mike -> Syd OS with upstream credit; note that
  production signups are disabled (email+password behind Cloudflare Access).

Both apps build clean (tsc; next build with Supabase env set).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>