feat(projects): add typed project tool outputs - #3401

Summary

Migrates projects_list, projects_get, and projects_write to typed inputs/outputs with structured output exposed only for protocol 2026-07-28.

Why

Next sequential layer of native stack #3385, on parent #3399 (c6acd4d330ecaf4149f98dc3b3e82f74be586af9).
Fixes #

What changed

• Added typed compatibility inputs that preserve legacy method-specific validation, coercion, and error precedence.
• Added concrete method-selected output unions/schemas; arbitrary-only fields (value, batch ref, error candidates) are explicitly patched.
• Kept text output, pagination, feature flags, and OAuth scopes unchanged; legacy/unknown protocols hide output schema and structured content.
• Added protocol wire tests, schema contract/negative tests, and typed toolsnaps; regenerated README docs.

MCP impact

• No tool or API changes
• Tool schema or behavior changed — input schemas gain compatibility fallbacks and modern sessions receive output schemas/structured content; legacy behavior is preserved.
• New tool added

Prompts tested (tool changes only)

• Covered by 21 exact wire cases across 2026-07-28, 2025-11-25, empty, and unknown protocols, plus a temporary exact-parent oracle (passed, then removed).

Security / limits

• No security or limits impact
• Auth / permissions considered — scopes unchanged.
• Data exposure, filtering, or token/size limits considered

Tool renaming

• I am renaming tools as part of this PR (e.g. a part of a consolidation effort)
  • I have added the new tool aliases in deprecated_tool_aliases.go
• I am not renaming tools as part of this PR

Lint & tests

• Linted locally with ./script/lint — passed, 0 issues
• Tested locally with ./script/test — passed

Ordered validation: UPDATE_TOOLSNAPS=true go test ./... passed → script/lint passed → script/test passed → script/generate-docs passed → git diff --check passed.

Docs

• Not needed
• Updated (README / docs / examples)