refactor: consolidate built-in tool registration and dispatch

[Qiyuanqiii]

Summary

Built-in tool definitions, valid names, action classes, project-config IDs, payload normalization, and Gateway dispatch were maintained in separate lists. This allowed advertised GitHub review evidence tools to miss dispatch and code-intel calls with valid authority to be rejected by the Store.

Create one ordered registry in internal/toolgateway/registry.go and derive those lookups and dispatch paths from its entries. The Agent's static admission check now uses the same registry. Remove the old lists, dispatch switch, and unused tool-name helpers: production Go code is reduced by 87 lines.

• Include the existing code-intel tools and browser scroll/key tools in CLI schema listing and lookup.
• Route both GitHub review evidence tools through their existing Agent Code executor.
• Persist code-intel calls through the existing Agent Code authority decoder, retaining Run binding and canonical serialization.
• Preserve model advertisement order, phase selection, dynamic capability schemas, policy/budget checks, ScriptProcess's separate execution path, and historical ledger compatibility.

This PR is based on #246 (codex/clarify-runtime-names) so its diff contains only this 16-file registry change. Merge the naming PR first, then retarget this PR to main.

Validation

• GOTOOLCHAIN=go1.26.6 go test ./internal/toolgateway -count=1 — full package passes.
• Go 1.26.6: all packages compile and 19 selected app/application/store tests pass, covering tool admission, dynamic capabilities, CLI schema queries, policy denial, restart recovery, ledger compatibility, and code-intel authority persistence.
• New regressions exercise GitHub evidence dispatch through the existing gateway, successful code-intel storage/readback, and rejection of missing or cross-Run authority.
• git diff --check passes.

Surface governance

• No Surface is added, promoted, downgraded, deprecated, or removed.

• Registry item(s): N/A — no Surface change

• Target tier / transition: N/A — no Surface change

• Entry criteria / decision: N/A — no Surface change

• Owner: N/A — no Surface change

• Shared Go Application contract: N/A — no Surface change

• Authority impact: N/A — no Surface change

• Supported platforms: N/A — no Surface change

• Release / test evidence: N/A — no Surface change

• Compatibility strategy: N/A — no Surface change

• Deprecation window: N/A — no Surface change

• Removal / rollback plan: N/A — no Surface change

Audit

• No credentials or local runtime data are included.
• Policy, workspace, sandbox, and persistence boundaries were reviewed; existing runtime authority checks remain in place.
• Current architecture documentation describes the registry and runtime capability boundary.

Co-authored-by: Codex codex@openai.com