#15792: fix: pass agentId to resolveSessionFilePath in additional call sites

## Summary This PR fixes additional call sites where `resolveSessionFilePath()` was called without passing `agentId` in the opts parameter, which caused non-default agents to fail with "Session file path must be within sessions directory" error. ## Changes - `src/config/sessions/transcript.ts`: Pass `agentId` to `resolveSessionFilePath` in `appendAssistantMessageToSessionTranscript` - `src/agents/tools/sessions-list-tool.ts`: Pass `entryAgentId` to `resolveSessionFilePath` in session list tool - `src/agents/subagent-announce.ts`: Extract and pass `agentId` from sessionKey to `resolveSessionFilePath` in `buildSubagentStatsLine` - `src/gateway/server-methods/chat.ts`: Add `agentId` parameter to `resolveTranscriptPath` and `appendAssistantTranscriptMessage`, and pass it through from callers ## Testing - Verified that the code compiles without errors - All existing tests should continue to pass - The fix follows the existing pattern used in other call sites that were already fixed Fixes openclaw/openclaw#15761 <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR updates several call sites to pass an `agentId` into `resolveSessionFilePath()` so transcripts resolve under the correct per-agent sessions directory (fixing failures for non-default agents). The main behavioral change is in `src/gateway/server-methods/chat.ts`, where transcript path resolution now optionally threads through an `agentId` derived from the session key before appending injected assistant messages to the session transcript. <h3>Confidence Score: 3/5</h3> - This PR is close to mergeable but has one path-resolution bug that can misplace transcripts when storePath is customized. - Most changes correctly add `agentId` alongside `sessionsDir`, matching how `resolveSessionFilePath` expects to be called. However, `resolveTranscriptPath` in `src/gateway/server-methods/chat.ts` drops `sessionsDir` whenever `agentId` is present, which changes semantics and can resolve to the wrong sessions directory for custom store paths. - src/gateway/server-methods/chat.ts _{Last reviewed commit: 55385e3} <!-- greptile_other_comments_section --> _{(3/5) Reply to the agent's comments like "Can you suggest a fix for this @greptileai?" or ask follow-up questions!} <!-- /greptile_comment -->