Make OpenCode E2E green again

[Soph]

Summary

• Make turn-start synchronous (callHookSync) so session state is initialized before fast mid-turn commits hit git hooks
• Add fallback session/turn bootstrapping in message.updated for opencode run flows where message.part.updated fires too late
• Backfill prompts from OpenCode transcript on turn-end when turn-start sent an empty prompt
• Exclude agent-owned files (opencode.json, .opencode/) from session tracking via new ProtectedFilesProvider optional interface

Also handles #883

Test plan

• New tests for sync turn-start dispatch
• New tests for message.updated fallback (session-start and turn-start)
• New test for prompt backfill from OpenCode transcript
• New test for agent file exclusion in DetectFileChanges and FilterAndNormalizePaths
• New tests for AllProtectedFiles() registry function
• mise run check passes

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Note

Medium Risk
Adjusts OpenCode hook dispatch timing and lifecycle prompt backfill, which can change when sessions/turns are recorded and what files/prompts are attributed to a checkpoint.

Overview
Makes OpenCode hook execution more reliable in fast/non-interactive flows by switching turn-start to synchronous dispatch, adding a message.updated fallback to emit session-start/turn-start early, and centralizing per-session state resets via resetSessionTracking.

Extends the OpenCode agent with PromptExtractor support and updates lifecycle turn-end handling to backfill missing prompt metadata from OpenCode export transcripts (and update session state accordingly).

Improves session file-change attribution by filtering out agent-owned paths (e.g. .opencode/... and opencode.json) from change detection/normalization, with new tests covering the updated behaviors.

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[Copilot]

Pull request overview

Updates the OpenCode agent plugin so turn-start runs synchronously (blocking) to ensure session initialization completes before subsequent agent actions (and to avoid shutdown races), and adds a regression test to enforce the behavior.

Changes:

• Switch turn-start dispatch from async callHook to blocking callHookSync.
• Update plugin inline documentation to reflect the expanded sync-hook use case.
• Add a unit test verifying turn-start is dispatched via callHookSync.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
cmd/entire/cli/agent/opencode/hooks_test.go	Adds a regression test asserting turn-start uses the sync hook path.
cmd/entire/cli/agent/opencode/entire_plugin.ts	Changes turn-start hook dispatch to callHookSync and updates comments.

[Soph]

@cursor review

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