fix(session): follow compression continuations for transcript reads (#34089)

[teknium1]

Summary

Reading a compacted session by its old root id over HTTP now returns the live continuation transcript instead of an empty conversation — closing the last #34089 read-path gap for Desktop / remote API session readers.

Changes

• gateway/platforms/api_server.py: GET /api/sessions/{id}/messages resolves the id through SessionDB.resolve_resume_session_id() before loading messages, and returns the resolved live id.
• hermes_cli/web_server.py: same fix on the CLI/Desktop get_session_messages endpoint (after the existing prefix resolution).
• Regression tests for both endpoints: a root session compressed into a child continuation hydrates from the child tip.

Root cause

/resume already redirects through resolve_resume_session_id(), but the two message-read endpoints still called get_messages(root_id) directly. After compression the root has zero message rows (they live on the forked child), so readers got an empty transcript.

Validation

	Before	After
GET /messages on compacted root id	empty transcript, root id	child transcript, child id
tests/gateway/test_session_api.py + tests/hermes_cli/test_web_server.py	—	268 passed

Salvaged from #41520 by @konsisumer; original commit cherry-picked with authorship preserved. (Author already in AUTHOR_MAP.)

Infographic

[github-actions]

🔎 Lint report: hermes/salvage-41520 vs origin/main

ruff

Total: 0 on HEAD, 0 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 0 pre-existing issues carried over.

ty (type checker)

Total: 10114 on HEAD, 10111 on base (🆕 +3)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 5238 pre-existing issues carried over.

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