feat(extensions): project OpenCode tool hooks statically

[limityan]

Summary

This revision narrows PR1 to a runtime-free, production-consumed Hook projection slice:

• Add five ecosystem-neutral Rust values for Hook contribution identity, Hook point, declared data risks, incomplete safety facts, and the resulting static declaration.
• Reuse the existing OpenCode managed-package read path to inspect fixed .js / .ts package bytes with a workspace-pinned OXC parse-only profile.
• Read only static top-level properties from the exported plugin return object. Map tool.execute.before and tool.execute.after to typed declarations; report other real OpenCode Hook properties as projection-only.
• Emit explicit, stable diagnostics for unavailable Hook execution and AST parse failure. User-facing messages use OpenCode event names and natural-language risk descriptions.

Architecture and ownership

• product-domains owns only ecosystem-neutral facts. It has no OpenCode, runtime, worker, process, UI, or adapter dependency.
• opencode-adapter owns OpenCode syntax and semantic translation. OXC only extracts syntax-safe static property names; it does not execute TypeScript or interpret OpenCode behavior.
• The existing PluginHostAdapter::read_plugins projection is the only production consumer. There is no test-only consumer used to justify public APIs.
• Parse failure is fail-closed for Hook projection through opencode.hook_projection_parse_failed; ordinary payload strings, dynamic keys, and spread contents are not guessed as Hook declarations.
• Stable diagnostic codes and audit correlation identities remain separate from user messages. This PR adds no log sink or metric backend.

The previous external-sources resolver, ordering/override/terminal-decision API, reverse crate dependency, and cross-layer test have been removed. Public Hook contracts are limited to the five types consumed by the read projection.

Scope boundary

This pull request does not add:

• Node, Bun, or any other Hook runtime;
• module loading, workers, processes, handler registration, activation, dispatch, cancellation, or lifecycle ownership;
• Hook ordering, conflict resolution, enable/disable policy, persistence, or telemetry wiring;
• a TypeScript bridge, Tool Pipeline integration, targets, Desktop/Web/TUI/CLI UI, settings, or commands.

tool remains handled by the existing custom-tool projection. OpenCode event-bus event types remain payloads of the top-level event Hook and are not treated as Hook property names.

Performance and compatibility

• Parsing occurs once per managed package load, not on each read or dispatch.
• Inputs retain the existing limits of 64 files, 1 MiB per file, and 16 MiB per package.
• The oxc-parse workspace alias uses the already locked OXC version with default features disabled; the OpenCode adapter dependency graph does not pull transformer, codegen, or semantic features.
• Single-line expression bodies, block return objects, unsupported real Hooks, ordinary event-name string references, event-bus false positives, and parser failure are covered by managed-package integration tests.

CI root cause fixed

The previous Frontend Build failure came from core-boundary violations: an external-sources production dependency on the OpenCode adapter, a cross-layer test consumer, an unexpected public adapter module, and excess public resolver APIs. The final file set removes those paths and updates the public API budget/self-tests for the production read-projection consumer.

Validation

• cargo test -p bitfun-opencode-adapter: 90 passed.
• cargo test -p bitfun-product-domains: passed with the Hook target correctly feature-gated.
• cargo test -p bitfun-product-domains --features external-sources --test external_hook_contribution_contracts: 3 passed.
• node --test scripts/check-core-boundaries.test.mjs: 16 passed.
• node scripts/check-core-boundaries.mjs: passed.
• pnpm run check:repo-hygiene: passed.
• cargo check -p bitfun-core --features product-full: passed; four pre-existing MCP deprecation warnings remain.
• cargo check --workspace: reaches the Desktop build script and is blocked only because the local worktree does not contain the generated src/mobile-web/dist resource.
• git diff --check: passed.
• Independent adversarial product review: READY, no P0/P1/P2 findings.
• Independent adversarial architecture review on final commit e6c17b29b: READY, no P0/P1/P2 findings.

Follow-up boundary

Hook runtime selection, worker/process ownership, handler invocation, ordering, cancellation, recovery, UI, logs, and metrics remain a separate follow-up design and implementation. This PR does not pre-implement or imply those runtime decisions.