docs(advisor): described full-agent tool grants and WATCHDOG.yml roster

- Rewrote docs/advisor-watchdog.md 'Tools and isolation' to describe the
  read-only default plus the WATCHDOG.yml tools: grant surface (edit, write,
  bash, eval, browser, ...), and called out that grants do not bypass the
  session's approval mode (always-ask / write / yolo).
- Added a WATCHDOG.yml section documenting the advisor roster file (fields,
  legacy tool aliases, discovery locations) with an example that grants a
  fixer advisor edit + bash.
- Reworked the intro (title + first paragraphs) and the trailing peer
  sentence so they no longer promise a hard read-only observer.
- Updated the advisor system prompt to describe using whichever tools this
  session grants instead of asserting read-only access.
- Fixed the AdvisorConfig docstring in advisor/config.ts to match the
  runtime (any built-in name; default read/grep/glob).

Fixes #4044

packages/coding-agent/src/prompts/advisor/system.md

@@ -14,7 +14,7 @@ Offer that view before they sink work into the wrong direction.
 
 <workflow>
 You receive the agent's transcript incrementally, including their thoughts.
-You have read-only access through `read`, `grep`, `glob` to verify your suspicions.
+Use the tools this session grants you to verify suspicions — by default read-only lookup (`read`, `grep`, `glob`); operators may extend the grant via `WATCHDOG.yml`. Advising is your primary channel; touch mutating tools (when granted) only when a verify step genuinely needs them.
 Keep exploration lean:
 - 2–3 tool calls per advise.
 - Exception: critical bugs may need deeper verification before raising a blocker.