release: v0.17.9

[edwin-zvs]

Patch release bump: 0.17.8 → 0.17.9.

• Bumps [workspace.package] version in Cargo.toml (source of truth) and regenerates Cargo.lock
• Bumps Formula/construct.rb version (macOS checksums follow in a separate PR after the tag builds, since the release workflow's direct push to main is blocked by branch protection)
• brew style clean

Ships the work merged since v0.17.8:

• Fix TUI modal input precedence over Playbook #1292 Fix TUI modal input precedence over Playbook
• Fix WebUI Playbook editor font scale #1293 fix(webui): align Playbook editor font scale
• Fix TUI channel editor save UX #1294 Fix TUI channel editor save UX
• fix(tui): keep focus sweep visible on borders #1295 fix(tui): keep focus sweep visible on borders
• Fix WebUI Playbook ownership across split focus #1296 fix(webui): keep playbook in unfocused split pane
• fix(webui): match the TUI's per-character playbook run shimmer #1297 fix(webui): match the TUI's per-character playbook run shimmer
• fix(webui): C-Space sets the Playbook mark and motion extends the region #1298 fix(webui): C-Space sets the Playbook mark and motion extends the region
• feat(tui): replay the focus sweep when typing resumes after idle #1299 feat(tui): replay the focus sweep when typing resumes after idle
• fix(webui): let Tab focus the Playbook selection menu #1300 fix(webui): let Tab focus the Playbook selection menu

After merge: tag the merge commit v0.17.9 and push it to trigger the release workflow.