Match case and whole word in both find boxes, and skip what git ignores in Find in files

[a-team-app]

Summary

Both find boxes now have Case and Word checkboxes, and Find in files skips what git ignores, with an Ignored files checkbox to bring those files back.

• Find bar (Ctrl+F, file and diff tabs): ☐ Case ☐ Word sit between the query and the count. Alt+C / Alt+W toggle them from either field, and so does a click. The search re-runs straight away. The options are shared by every tab for the session. Replace and Replace all follow them.
• Find pane (Ctrl+Shift+F / Ctrl+Shift+H): Case and Word sit under the fields, with Ignored files below them. These options are separate from the bar's. In a repo, the pane searches what git ls-files --cached --others --exclude-standard lists, so .gitignore (nested ones too) and .git/info/exclude are honoured. Outside a repo, or if git fails, Ignored files is disabled, the old skip list applies, and the count reads e.g. 4 in 1 files (not a git repo).
• Tab still goes straight between Find and Replace. The checkboxes don't take focus.
• The palette and Edit menu offer Match case / Stop matching case, Match whole word / Stop matching whole word and Include ignored files / Skip ignored files. F1 and Settings list them as … on or off. Mnemonics are tmc, tmw and tfi. F1 in either box lists Alt+C / Alt+W.

Closes #527

Worth flagging

• Case/Word/Ignored files are Global commands, enabled only while a find box has the keys. The bar's keys are in the Editor scope and the pane's in Find, and no one scope covers both. So Settings › Keyboard Shortcuts shows them under Global. Anywhere else they're disabled, so Alt+C / Alt+W fall through as before.
• Whole word follows VS Code: if a query starts or ends with punctuation, that side counts as a word edge already, so .Id matches x.Id. _ counts as a word character, so _Id doesn't match Id.
• The pane's count line now wraps to a second row when it's too long, so (not a git repo) reads in full at the sidebar's default width of 30.
• In the bar, toggling an option re-runs the search from the current match, so the count can read 2 of 3 rather than starting again at 1.
• Checked with tuirec at 80×24, default sidebar width:
  • In the bar, Case + Word on TextSearch.cs gives 1 of 2, highlighting only .Id / x.Id.
  • With the replace row showing, F1 lists the Alt+C / Alt+W rows.
  • In the pane on this repo, Id with Case + Word gives 180 in 66 files.
  • Clicking Case toggles it.
  • tfi brings in bin/ and obj/ (10000+ in 472 files).
  • In a folder outside any repo, Ignored files is dimmed and bin/ is skipped.
  • The Edit menu shows Stop matching case Alt+C and dims Include ignored files when opened from the bar.
• Local test run: on this machine FocusHostTests and one HelpPlaceHostTests test hang on origin/main as well, so I didn't get a full run here. The classes this PR touches pass. CI is the full check.

🤖 Generated with Claude Code

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