docs: record history pagination diagnosis

.project-docs/30-worklog/tasks/20260831-diagnose-history-pagination-3eac1d7b.md

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+# Task: Diagnose older conversation history loading
+
+## Identity
+
+- Task ID: 20260831-diagnose-history-pagination-3eac1d7b
+- Mode: Feature
+- Branch: codex/20260831-diagnose-history-pagination-3eac1d7b-diagnose-history-pagination-3eac1d7b
+- Worktree: /Users/inmanx/Documents/makelore-diagnose-history-pagination-3eac1d7b
+- Base commit: 38f85f6b5e4dc4e2c5e5b9f8f4506554cfd578f5
+- Owner: codex
+- Status: Ready for Integration
+
+## Scope
+
+- Diagnose why older messages stop loading while scrolling upward in the
+  Makelore Code conversation shown in the supplied screenshot.
+- Trace Renderer scroll behavior, the public Snapshot/Host API contract,
+  Main-owned Pi session hydration, and the persisted session data for the
+  affected local conversation.
+- Make no product-source, dependency, runtime, account, or external-service
+  changes.
+
+## Intent And Constraints
+
+- Preserve the Main-owned Pi `0.84.2` and product-neutral Snapshot/Patch
+  boundary; do not introduce or infer a Renderer-to-Pi history path.
+- Treat the running development worktree, application logs, project metadata,
+  and Pi session files as read-only evidence.
+- Distinguish persisted-data loss from a bounded projection or missing UI/API
+  pagination mechanism.
+
+## Outcome
+
+- Identified a deterministic two-layer history-display boundary rather than a
+  transport stall or corrupt session.
+- The affected Pi JSONL remains intact at 343 records / 782,976 bytes. Its
+  active branch contains 342 entries from 2026-08-28T08:34:53Z through
+  2026-08-31T11:25:59Z, with all parent links traversable to the current leaf.
+- The branch contains one compaction. `projectPiSessionSnapshot()` calls
+  `retainedTail()`, which intentionally discards every active-path entry before
+  the compaction's `firstKeptEntryId`. For this session that hides 136 records,
+  including 128 raw messages and approximately 131 product timeline nodes.
+  The first retained record begins at 2026-08-29T06:11:52Z.
+- The remaining tail projects to approximately 195 timeline nodes. Renderer
+  shows the newest 120 nodes and the `加载更早内容` button only increases that
+  in-memory window by 100. Its scroll handler merely tracks stick-to-bottom;
+  it does not request older history.
+- The public Snapshot contract and `/snapshot` route expose no history-page
+  cursor or `before` parameter. After the one in-memory expansion reaches all
+  195 projected nodes, no additional Main/Pi request is possible even though
+  the omitted records are still on disk.
+- No product source, dependencies, runtime, account, session, or external
+  service were changed.
+
+## Verification
+
+- Parsed the affected `.makelore/conversations.json` binding and its exact
+  managed Pi JSONL without writing either file.
+- Counted JSONL record types, reconstructed the current leaf-to-root active
+  path, checked the compaction boundary, and counted retained versus omitted
+  messages/product nodes.
+- Inspected `CodingConversationTimeline`, the Renderer conversation Store,
+  shared Snapshot contract, Coding Host route, Pi runtime hydration,
+  `session-projector`, and Agent Server `get_entries` behavior.
+- Confirmed current unit coverage explicitly expects pre-`firstKeptEntryId`
+  history to be absent and covers only in-memory window expansion.
+- Searched the current Main log and found no `CODING_SESSION_UNREADABLE`,
+  missing-entry, or history-load error for this incident.
+- No tests were run because this was a read-only diagnosis with no behavior
+  change; the isolated worktree has no installed `node_modules`.
+
+## Follow-ups
+
+- If a fix is requested, keep the full active-branch history available for UI
+  display independently of the compacted model-context tail. Add a bounded
+  older-history cursor/route (or, as a minimal correction, project the full
+  active path) and make Renderer prepend pages while preserving the scroll
+  anchor. Keep the compaction summary private and retain Snapshot/Patch as the
+  product-neutral boundary.
+
+## Promotion Candidates
+
+- None recorded.