perf: preserve unchanged thread row identities

[kalvinnchau]

Summary

• retain unchanged thread root/reply objects and reply arrays across status changes and pagination
• preserve selected-profile map identity for equivalent participant sets while keeping relevant profile updates visible
• stabilize video seek callbacks and avoid broad profile subscriptions when selected profiles are supplied
• add mounted StrictMode regressions through the real relay session for pagination, status, edits, signed profile updates, and video seeking; unrelated profile updates still invalidate mounted rows through the shared name service

Validation

• pre-push typecheck and full Vitest: 208 files / 2,212 tests passed with VITEST_MAX_WORKERS=2
• build: passed
• Chromium and WebKit journeys covering thread history, unread state, profiles, and measurement prerequisites: 24/24 passed
• plugin-manager Rust tests: 21 passed
• adversarial reviews from cyberpunk and cid: no unresolved findings, 9/9/9 at 68952d358b614e497aacb6f23ce52b2349983970

Limitations

• the selected-profile map retains identity for unrelated profile updates, but the shared identity-name subscription still rerenders mounted rows; this PR does not optimize name invalidation

• no matched production capture, so this PR makes no latency or percentage-speedup claim

• the Node integration gate previously encountered environment-specific temporary executable/shebang permission failures (73 passed / 19 failed)

• live 100+ reply thread validation remains unperformed

[wesbillman]

Carl, an automated reviewer, commenting via Wes’s GitHub account.

Changes requested at ea234c1feacf3daf5eb416b68bb6b4d1bd1522af against base 6e6417d713235dcfc29969f38f278ef51c8e7d82: one P2 in the mounted performance regression, detailed inline. The test bypasses a production subscription that defeats its zero-render assertion. No additional material defect found in row equality, pagination/status sharing, access purges, or callback freshness.

Merge criterion: exercise profile updates through the intact session and either satisfy the intended isolation or explicitly test/document the narrower optimization. Do not expand the identity subsystem just to satisfy an overstated test.

Validation: exact-head hosted CI passed, including full Vitest, Node integration, Rust, Chromium/WebKit journeys and measurements. Locally, the original full identity-test file passed; the test-only real-producer variant failed at the reported assertion; a diagnostic variant confirmed the four renders and passed the remaining checks. No broad local rerun, live 100+ reply thread, actual media-playback acceptance or matched production performance capture. Windows native CI was skipped.

[wesbillman]

Carl, an automated reviewer, commenting via Wes’s GitHub account.

No remaining blockers at f545f1c43b07a92352ec32972be4bbdab4d1bf9e against base 6e6417d713235dcfc29969f38f278ef51c8e7d82. The P2 is resolved under the agreed narrower contract: the test keeps the intact session, feeds signed kind-0 events through its real profile/name producer, and explicitly asserts the remaining four StrictMode body renders. Pagination, edit, relevant-name and seek-callback checks remain. The PR description now disclaims name-invalidation isolation. No production code changed since the previous review.

Verified CI for this head: all automatic Linux lanes passed; the revised test passed within the full 223-file / 2,357-test Vitest run. CI checked merge 7f598ef of this head into the stated base. No redundant local rerun. Existing limits remain: no matched production speedup capture, live 100+ reply exercise or actual media-playback acceptance; Windows native validation skipped.

This is a non-approving re-review. The prior change request is obsolete; formal approval remains with an authorized reviewer.

Carl, an automated reviewer, commenting via Wes’s GitHub account. P2 resolved and verified at f545f1c; superseded by the non-approving re-review. No remaining blockers.