fix(cosh): set run_id before UserPromptSubmit hook fires

[kongche-jbw]

Description

UserPromptSubmit hook input was carrying a stale run_id (or undefined
on the very first prompt). GeminiClient.sendMessageStream() used to fire
the hook through messageBus.request BEFORE calling
config.setCurrentRunId(prompt_id), so when
hookEventHandler.createBaseInput() read config.getCurrentRunId() it
saw the previous prompt's value.

Fix:

• Promote setCurrentRunId(prompt_id) to run right after the
  isContinuation guard, before any UserPromptSubmit hook activity.
• Remove the now-duplicate setCurrentRunId from the later non-continuation
  initialization block.
• Continuations (tool-result follow-ups, Stop hook, next-speaker
  Please continue.) still skip the call so they keep the original
  prompt's run_id, consistent with the [cosh] bug: UserPromptSubmit Hook 在单次prompt 运行过程中会被调用多次 #530 fix.

recordUserMessage and stripThoughtsFromHistory are intentionally NOT
moved earlier — block / ask / additionalContext semantics on
UserPromptSubmit must keep working.

Related Issue

closes #531

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional change)
• Performance improvement
• CI/CD or build changes

Scope

• cosh (copilot-shell)
• sec-core (agent-sec-core)
• skill (os-skills)
• sight (agentsight)
• tokenless (tokenless)
• Multiple / Project-wide

Checklist

• I have read the Contributing Guide
• My code follows the project's code style
• I have added tests that prove my fix is effective or that my feature works
• I have updated the documentation accordingly
• For cosh: Lint passes, type check passes, and tests pass
• For sec-core (Rust): cargo clippy -- -D warnings and cargo fmt --check pass
• For sec-core (Python): Ruff format and pytest pass
• For skill: Skill directory structure is valid and shell scripts pass syntax check
• For sight: cargo clippy -- -D warnings and cargo fmt --check pass
• For tokenless: cargo clippy -- -D warnings and cargo fmt --check pass
• Lock files are up to date (package-lock.json / Cargo.lock)

Testing

Three new regression tests in
src/core/client.test.ts → sendMessageStream → UserPromptSubmit hook firing semantics:

1. sets currentRunId before firing UserPromptSubmit so hook input has the right run_id —
   Uses invocationCallOrder to assert setCurrentRunId(prompt_id) runs
   before the UserPromptSubmit request hits the bus.
2. exposes the current run_id to hook handlers at UserPromptSubmit request time —
   Links setCurrentRunId / getCurrentRunId and has the bus subscriber
   capture getCurrentRunId() exactly as createBaseInput() would,
   asserting the captured id equals the prompt id.
3. keeps the original run_id during a continuation call — Pre-seeds the
   run id, calls with { isContinuation: true }, asserts
   setCurrentRunId is not invoked and the run id is untouched.

Commands run:

cd src/copilot-shell && npm run test --workspace=packages/core -- src/core/client.test.ts
# 56/56 tests pass

Additional Notes

Only client.ts and client.test.ts are changed. No dist/,
coverage/, package.json, or package-lock.json modifications.
This stacks on top of the #530 fix as
0764474 fix(cosh): fire UserPromptSubmit hook only on real user prompts.

[samchu-zsl]

LGTM, thx!