docs: adopt four-bucket docs layout and progressive AGENTS index

[azi44eo]

Align the code repository around four authoritative documentation buckets — architecture/, guideline/, specs/, and plans/ — and turn the root AGENTS files into progressive-disclosure indexes.

Summary

• Add complete indexes for the four authoritative documentation buckets and route root AGENTS guidance through standards, architecture, cross-cutting, and task-based maps.
• Move stable architecture, repository operations, feature specs, implementation plans, and SDLC governance material to their owning buckets.
• Add documentation governance, command, verification, logging, host/remote, agent-loop, theme, and Spec/Plan template guidance.
• Keep code-coupled Feishu setup and release-download verification guides in this repository.
• Preserve public paths used by released clients and durable links with compatibility pointer pages; canonical content has one owner.
• Preserve the existing performance audits and SDLC external research as dated, non-normative references instead of deleting them.
• Preserve existing normative meaning, including the absolute tokio/full prohibition and owner-scoped Rust verification.

Type and Areas

Type: documentation / repository governance

Areas: root AGENTS and contributor entrypoints, docs/, Web UI documentation URLs, appearance audit documentation paths

Motivation / Impact

The old layout mixed stable architecture, operational rules, feature designs, plans, product setup guides, research, and temporary-process paths. The new layout gives each durable document one canonical owner while keeping high-frequency rules discoverable within two hops from AGENTS.md.

There is no product-logic change. User-visible impact is limited to documentation/help links, and legacy public paths remain reachable for already released clients.

Migration Map

Old location	Canonical location / disposition
docs/development/{i18n,releasing,ui-testids*}	docs/guideline/
docs/remote-connect/feishu-bot-setup*	docs/guideline/feishu-bot-setup*; old paths retained as compatibility pointers
docs/verify-downloads*	docs/guideline/verify-downloads*; old paths retained as compatibility pointers
docs/features/{agent-hooks*,remote-workspaces,session-runtime-usage-report-design}	docs/specs/; old public paths retained as compatibility pointers
docs/superpowers/specs/*	docs/specs/*
docs/superpowers/plans/*	docs/plans/*-plan.md
docs/sdlc-harness/architecture/* and design.md	docs/architecture/* and docs/architecture/sdlc-governance-architecture.md
docs/sdlc-harness/features/*, product requirements, metrics, and traceability	docs/specs/*
docs/sdlc-harness/{implementation-plan,agent-workflow-staged-plan}.md	docs/plans/sdlc-governance-*.md
docs/sdlc-harness/governance/self-governance-notes.md	docs/guideline/self-governance-notes.md
docs/sdlc-harness/research/external-research.md	docs/specs/sdlc-governance-external-research.md as a dated non-normative reference
docs/performance/01-compile-performance.md	docs/plans/2026-08-14-compile-and-dependency-governance-plan.md
docs/performance/02-04 reviews	Dated reference documents under docs/specs/; implementation requires revalidation
docs/sdlc-harness/README.md	Navigation and stable boundaries folded into docs/architecture/sdlc-governance-architecture.md
Empty docs/specs/templates/plan.md introduced by the initial migration	Removed; the canonical plan template is docs/plans/templates/plan.md

Compatibility / Reviewer Notes

• The final PR has no dependency on an external bitfun_doc repository.
• Compatibility pages contain no duplicated authority; they only point to canonical pages and are indexed in docs/README.md.
• Verified on the PR head that legacy Feishu, download-verification, and Agent Hooks URLs return HTTP 200.
• No remote runtime scenario changed. The only product path touched is a documentation URL, with the released-client path preserved.

Verification

• git diff --check
• pnpm run check:repo-hygiene
• pnpm --dir src/web-ui run gen:types — 34 tests passed
• pnpm run type-check:web
• pnpm run appearance:contract-audit — passed; 16 existing advisory warnings
• Scripted local Markdown path audit — no new missing local links versus the base snapshot
• Canonical directory/index inventory audit — 0 unindexed pages
• Manual old-to-new mapping review against docs/README.md and docs/guideline/docs-governance.md

Checklist

• This PR is focused and does not include secrets, temporary prompts, generated scratch files, or unrelated artifacts.
• Relevant verification is recorded above, or skipped checks are explained.
• User-facing strings, docs, and locales are updated where applicable.

[GCWing]

The document status is inconsistent with the current repository, and since the document affects AI behavior—yet repository-side maintenance of it will be reduced going forward—this PR will not be merged.