fix(mobile): preserve exact mention recipients in saved drafts

[loganj]

🤖

Summary

Saved drafts remembered their text but not exactly who each mention referred to: reopening a draft (or restarting the app) could re-bind a mention to the wrong same-name teammate, and a draft restored in one thread could capture text arriving for another. This PR saves the exact selected identities alongside the draft text and restores them together, so a reopened draft names the same recipients — with their agent markings — that you picked, including after a failed send.

• Persists selected keys and agent presentation in the app's existing per-account/channel/thread draft storage (device-local; no cross-device portability claim).
• Restores recipient bindings before text listeners run, including recovery from a rejected send; malformed legacy entries are ignored rather than guessed.
• Retires the previous draft's listeners before restoring another, so switching threads can no longer write incoming text into your outgoing draft.

Related issue

• Fixes: N/A. No separate issue; the related work is the stack below.
• Depends on fix(mobile): bind same-name mentions to exact selected identities #7385 (declared base) — same-name selections and qualified labels come from that PR.
• Landing note: branches in this series overlap in the composer — when rebasing, keep exact/durable mention bindings, the explicit invite/reference-only choice, the account/visit/revision fences, and authorization before membership preparation and publication; don't resolve conflicts by taking either side wholesale.
• Draft — not requesting merge yet; the security advisory doesn't run on this stacked base (it reviews main-based ranges).

Testing

• Regressions cover two namesakes, restart, rename, rejected send, a second restart, and changing draft scope.
• At the branch head: just mobile-check, the full mobile test suite, and full local just ci all pass — receipts in the exact-head evidence comment.
• Verification is widget-test level; no native device or simulator run is claimed.

To see it: mention an agent or a namesake, leave the channel, restart the app, and return — the draft still names the exact recipients you picked.

Screenshots

Flutter production-widget test renders — not native-device screenshots or acceptance captures.

Scenario	Before	After
Draft reopened after leaving the channel and restarting the app

Capture provenance

Rendered by the Flutter widget engine in a flutter test run (production widgets, production theme; no device or simulator). Before: this PR's declared base 39afd73b0adfde14164f4b10dbd089cb498312b6. After: its head 8a781108507dc4501192b0101185decc1ed6f118.

[loganj]

Independent durable-mention readiness evidence — 2026-09-07

Verified current stacked range: fix/mobile-exact-mentions-20260905 at 39afd73b0adfde14164f4b10dbd089cb498312b6 → 8a781108507dc4501192b0101185decc1ed6f118; +274/−23 = 297 across 8 files. Still OPEN/draft. Reconciliation only — no source changes, pushes, or test reruns.

• Local, exact final head (isolated TMPDIR and worktree-local targets): just mobile-check exit 0; full just mobile-test exit 0 (2,084 passed); full just ci exit 0. Receipts: WORK_LOGS/MENTIONS_REVIEW_A24EBE91/7387/final/ (results.txt: mobile-check=0, mobile-test=0, ci=0). The rebase from 6fd3b66b kept a byte-identical incremental diff (SHA-256 recorded).
• Durable-binding semantics covered by regressions on this head: one preferences snapshot for text + exact bindings, binding-only replacement, restoration before text notify, owner/account/community/thread-fenced listeners, failed-send recovery, and a second restart before retry.
• Remote: CI run 34137043290 completed success at this exact head. Rollup: 30 success / 25 intentional skips; nothing pending or failing.
• Rendered-chip acceptance also passed 39/39 at this head (same matrix as fix(mobile): bind same-name mentions to exact selected identities #7385, including the Desktop fix(desktop): restore mention chip identity icons #7338 @/robot glyph-regression parity; see the fix(mobile): bind same-name mentions to exact selected identities #7385 evidence comment).
• Advisory security: intentionally ineligible on this stacked (non-main) base — the trusted workflow rejects non-main bases and its skipped jobs are not required merge gates. No bypass or base change was attempted. The parent's authorized advisory attempt did not complete (40m0s timeout, no findings); see fix(mobile): bind same-name mentions to exact selected identities #7385.
• The PR body's composed-stack reference (40630565) predates the mention repairs and is stale relative to this head; no new composed-tree testing is claimed.
• Widget evidence only; no native device/simulator. Draft retained; no merge requested.

2026-09-07 update: the stale composed reference described above has been retired — the verify/mobile-combined-20260905 remote branch at 40630565 was deleted and the composed-stack sections were removed from all 11 PR bodies (no replacement combined-testing claim was made). This comment's 2026-09-07 evidence statements are preserved as historical record. Receipt: WORK_LOGS/COMPOSED_REFERENCE_RETIREMENT_A4B214BD/REPORT.md.