fix(skills): stop claiming -f/-v are universal in webcmd-usage

[Agnik47]

Problem

The webcmd-usage skill's "Universal Flags" section claimed -f/--format
and -v/--verbose work everywhere. Neither does:

• -v is missing from most plugin/profile/session/adapter/daemon
  built-ins
• -f is missing from every pure-action built-in (plugin install/update,
  adapter override, profile create/rename/use, daemon restart/stop,
  browser init)

The original issue's specific examples (e.g. browser network --format json)
no longer exist in the command surface, but the underlying claim of
universality is still wrong and worse than the issue described.

Fix

Replace "Universal Flags" with "Format and Verbose Flags": state that support
is command-specific, add a breakdown table of exactly which built-ins take
each flag, and point agents at <command> --help as the authoritative check
rather than a table that will go stale as commands change.

Edited both skill-src/webcmd-usage/SKILL.src.md and the generated
skills/webcmd-usage/SKILL.md (identical change — this file has no
@[...] imports in the edited region, so the generator is an identity
transform here).

Closes #173.

Verification

• Ran --help on ~24 affected commands (list, validate, skills,
  plugin search, browser verify, session create/list/close,
  profile list, auth status/refresh, doctor, web fetch,
  browser tabs/run/bind/snapshot/close, plugin install/update,
  browser init, profile create/rename/use, daemon restart/stop,
  adapter override) and confirmed every table entry against the actual
  flag output.
• npx vitest run --project unit src/skills.test.ts src/docs-sync-review.test.ts src/hosted/manifest.test.ts — 76 pass.
• Diffed SKILL.src.md against generated SKILL.md to confirm they match.

[github-actions]

🟢 No documentation gap found — medium confidence

The automated review found no documentation gap in the supplied changes.

This review is advisory and does not block merging.