Add doc-auditor agent and wire it into full-eval

Read-only documentation drift auditor: checks every README/instruction/HTML claim against the code and reports what no longer matches, modeled on the janitor/reviewer wrappers. Added to the full-eval suite (always-run) and to the subagents handbook roster and length budgets.

guides/full-eval.md

@@ -21,8 +21,10 @@ intent, and any focus area you were given.
 1. **evaluator** — full six-lens assessment of this repo.
 2. **security-auditor** — adversarial audit of this repo.
 3. **exerciser** — build, run, and black-box test this repo.
-4. **start9-spec-checker** — only if Phase 1 found StartOS-wrapper markers.
-5. **reviewer** — only if there are uncommitted changes; scope = the working diff.
+4. **doc-auditor** — claim-by-claim documentation drift audit (READMEs, instruction
+   files, public-facing HTML) against what the code actually does.
+5. **start9-spec-checker** — only if Phase 1 found StartOS-wrapper markers.
+6. **reviewer** — only if there are uncommitted changes; scope = the working diff.
 
 Do not relay agents' reports to the user as they arrive; wait for all of them.
 
@@ -55,8 +57,8 @@ P0 → P3, every finding from every agent exactly once, each one line:
 [Px] finding — evidence pointer — source agent(s)
 
 ## Scorecard
-The evaluator's lens table, adjusted only if another agent's evidence contradicts it
-(note any adjustment).
+The evaluator's lens table, adjusted only if another agent's evidence contradicts it —
+e.g. the doc-auditor's drift findings sharpen the Documentation lens (note any adjustment).
 
 ## Disagreements & gaps
 Where agents conflict, or where every agent's Coverage section shows the same blind