core: offer Reload in the read-only banner so the window picks up the change - #2265

@Birfy — review request at this tip: 4cf69b209b4980f9efdfc85998c08a11672cf972.

Tree 1795cfb62431e704d79b209953017ddf4ec9ca29, single parent / base 55503e16b359f034d71328f920aae6bbf674e0d1 (that is the live main, #2275's merge commit). 13 files +5996/−4469 — the bulk is generate re-laying the client bundle on the new base; the hand-written files are core/src/client/*, core/test/*, changelog.d/2247-*, plus docs/subsystems/core-client.md at exactly +1/−0 (the #2247 bullet).

State: ready (not draft), maintainer_can_modify: true, mergeable: true. Checks at this tip: tests-ok success, enqueue-guard success, merge-gate success, judge success, package success, plugins (social/tree/timeline/workflow) success, agent-audience success, reviewed tip success, risk tier success, ubuntu-latest · Node 24 success.

Evidence: TZ=UTC ARCH_DOCS_BASE=55503e16… npm run verify exit 0, 4656/4656/0, arch-docs: OK (13 changed file(s)); build-client --check exit 0; patches check 10/10 with core/ equals ds-bot/ + patches/ds-bot/; canonical no-op and a second generate writes nothing. Red-first on a clean 55503e16 tree carrying only the two new tests: 6 tests / 1 pass / 5 fail. The rebase from 172f9c6a to this tip changed no hand-written line: the tip-to-tip delta is byte-identical, after normalisation, to #2275's own merge delta.

Verdict: PASS at 4cf69b2
Written-by: Reviewer
Attestation: 4cf69b2 role=Reviewer

Ran at this tip:

$ cd core && node --import ./test/harness-resolve.mjs --test test/sidebar-readonly-reload.test.js test/client-reload-state.test.js
# tests 7  # pass 7  # fail 0
$ cp /data/dsh/bot/workspace/2265base/core/src/client/sidebar.js src/client/sidebar.js && node --import ./test/harness-resolve.mjs --test test/sidebar-readonly-reload.test.js test/client-reload-state.test.js
# red first, sidebar.js at the base blob  —  # tests 7  # pass 3  # fail 4
$ node core/scripts/build-client.mjs --check
# exit 0
$ node scripts/ds-bot-patches.mjs check
# ok 10 patches apply cleanly in order; ok core/ equals ds-bot/ + patches/ds-bot/

Read at tip 4cf69b209: all 16 check-runs success — tests-ok, ubuntu-latest · Node 24 · DSH 0.2.0-rc.2, plugins (social/tree/timeline/workflow), package, merge-gate, enqueue-guard, judge, agent-audience, reviewed tip, risk tier. mergeable: true, mergeable_state: clean, no hold, one comment at 10:06:20Z (the author's review request, not a stop request). Tier in the body is risk:T1 and that label is advisory only; merge-gate recomputes it at the queue entry, and this diff touches client sources, tests, one subsystem doc, a changelog fragment and the generated bundle — the shape T1 already sees on #2275/#2277.

What the change does, and why it holds:

• core/src/client/sidebar.js:372 — the Reload button is built once and rendered as its own row in both the wide and the rail shape, outside the role="status" banner. That preserves the live-region invariant the file already states in prose: a status region must stay text, or every announcement reads the button. Red-first shows exactly this half: with the base sidebar.js the Reload-control cases in both shapes go red (4 of 7).
• core/src/client/sources.js:26 — stateRequest drops since for a fresh read, so the host re-reads readOnly instead of answering a delta; stateAnswerIsStale keeps the revision/model skip for the poll and lifts it only for fresh (an unchanged answer is still never indexed). The two cases in client-reload-state.test.js pin both directions.
• core/src/client/index.js:169 — reloadTeam is a pull({ fresh: true }) under a reloading counter, and the poll loop stands back 200 ms while one is in flight. That closes the real race the comment names: the loop's unchanged answer otherwise takes the applied slot first and the full answer the press asked for is dropped as older.
• A failed reload goes through actions.reportError(error, 'reload'), the sidebar's own error channel, rather than an unhandled rejection.
• Generated files are consistent with their sources: build-client --check exit 0, ds-bot-patches check says 10 patches apply cleanly in order and core/ equals ds-bot/ + patches/ds-bot/. The large patches/ds-bot/0008-client-bundle.patch churn is the usual re-alignment on a new base, and the mirrors under patches/ds-bot/files/test/ carry the two new test files.
• No conflict markers in core/src/client, core/test, docs/subsystems or changelog.d.

Not run: the full verify (only the two changed test files were run, per the review budget), oxlint on its own (no binary in the shared node_modules; CI's test job already ran the lint chain green at this tip), and no live-runtime probe of the banner in a browser.

Body housekeeping done alongside this PASS: Reviewer: Reviewer added (the body carried Owner: Dev2 only), agent-pr added to the labels (only risk:T1 was set), and the ## Checkpoint block written for the queue entry's read.