Show matched token and query title in output

[shouze]

Summary

Two improvements to --no-interactive output (markdown and JSON):

1. Show matched token in each result line

Current (markdown):

- **org/repo** (1 match)
  - [ ] [src/foo.ts:3:5](https://github.com/org/repo/blob/main/src/foo.ts#L3)

Proposed:

- **org/repo** (1 match)
  - [ ] [src/foo.ts:3:5](https://github.com/org/repo/blob/main/src/foo.ts#L3): `useFlag`

Current (JSON matches[] entry):

{ "path": "src/foo.ts", "url": "...", "line": 3, "col": 5 }

Proposed:

{ "path": "src/foo.ts", "url": "...", "line": 3, "col": 5, "matchedText": "useFlag" }

The exact matched token is already available in TextMatchSegment.text — no API change required.
Falls back gracefully (no extra field) when location data is unavailable.

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2. Add a query title heading

Current:

1 repo · 2 files · 3 matches selected

Proposed (plain query):

# Results for "useFlag"

1 repo · 2 files · 3 matches selected

With qualifiers:

# Results for "useFlag" · including archived · excluding templates

1 repo · 2 files · 3 matches selected

Regex mode (query = /useFlag/i):

# Results for `/useFlag/i`

1 repo · 2 files · 3 matches selected

The heading also appears in --output-type repo-only mode (before the repo list).

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Motivation

• Makes piped/saved markdown documents self-describing without consulting the replay command
• The matchedText field makes JSON output directly usable in downstream scripts without needing to re-fetch content
• Regex users can immediately see the pattern that was applied at a glance

Implementation notes

• New exported function buildQueryTitle(query, options) in src/output.ts
• Uses isRegexQuery() from src/regex.ts to detect regex syntax
• matchedText uses TextMatchSegment.text (already in existing types — no type changes needed)
• Both changes are purely in src/output.ts (pure function layer)

Acceptance criteria

• buildMarkdownOutput prepends # Results for ... with correct qualifiers
• Each match line in markdown ends with : `{matchedText}` when location is available
• JSON matches[] includes "matchedText" when location is available
• repo-only mode also gets the H1 heading
• bun test passes with new and updated tests
• bun run lint, bun run format:check, bun run knip pass