i18n: localize Me propose-card residue (override_sheet + 4 source snackbars)

[agentfleets]

Closes #222

🤖 Generated with Claude Code

Co-Authored-By: deepseek-1 deepseek-1@users.noreply.github.com

[physercoe]

Thanks — the five source snackbars and the override buttons are done correctly: vocab axes are right (deliverable neutral; {project}/{task} via entityProject/entityTask), ARB is lockstep, and the static-helper ref threading avoids the #211 trap cleanly.

Requesting changes for 4 user-visible strings still hardcoded — the Done bar is "zero hardcoded user-visible strings remain in all five files", and these are visible labels. (My ticket's literal count undercounted them — both the multi-line hintText and the viewSourceLabel: button labels slipped a same-line grep. Scope is still "localize all user-visible strings", so please catch these.)

1. override_sheet.dart:191 — the reason-field hintText:

   hintText:
       'Why are you overriding the addressee\'s decision?',

   Add overrideReasonHint. No placeholder, so the apostrophe is safe in plain ARB — keep it as Why are you overriding the addressee's decision? (do not escape).

2. propose_card_deliverable.dart:88 — viewSourceLabel: 'View deliverable'. deliverable is neutral (same choice as the snackbar) → add a plain key e.g. viewDeliverable = View deliverable.

3. propose_card_phase.dart:86 — viewSourceLabel: 'View project' → role-bound, View {project} via vocab.term(VocabAxis.entityProject).title (you already read vocab for the snackbar in this file — reuse it; this label is built in build() where ref is in scope).

4. propose_card_task.dart:118 — viewSourceLabel: 'View task' → View {task} via vocab.term(VocabAxis.entityTask).title (same as #3).

Note propose_card_project_create.dart already localizes its viewSourceLabel to l10n.viewSpec — mirror that shape for the three above. After fixing, re-run bash scripts/lint-arb.sh + bash scripts/lint-vocab.sh and confirm gh pr checks 224 is all-pass before flipping back to ticket:in-review.

[physercoe]

Re-reviewed: the 4 missed strings are localized (override hint + View deliverable/project/task), casing fixed to .lower, and the task card test updated for the themed entityTask ('Ticket' under tech → 'View ticket'). All 4 checks green. Merging.