feat(continuous-learning-v2): make observer model configurable via ECC_OBSERVER_MODEL (#2390)

* feat(continuous-learning-v2): make observer model configurable via ECC_OBSERVER_MODEL

The observer hardcoded `--model haiku`. Parameterize as "${ECC_OBSERVER_MODEL:-haiku}": the haiku default is preserved (no behavior change for existing users), but users can opt into a stronger model — e.g. `ECC_OBSERVER_MODEL=opus` — for higher-quality instinct extraction. Useful on subscription plans where model cost isn't the limiting factor.

* fix(continuous-learning-v2): address review — update wiring test + docs

- Update source-inspection test to assert the ${ECC_OBSERVER_MODEL:-haiku} defaulting behavior (was matching the literal `claude --model haiku`, which this PR changed). All 31 tests pass.
- Add guidance to raise ECC_OBSERVER_TIMEOUT_SECONDS for slower models (e.g. opus) so the 120s watchdog doesn't kill analysis mid-run.
- Fix now-stale 'Haiku session' comment -> 'observer session' (model is configurable).

skills/continuous-learning-v2/agents/observer-loop.sh

@@ -241,11 +241,15 @@ PROMPT
   # on all platforms, not just when the observer happens to be launched from the project root.
   cd "$PROJECT_DIR" || { echo "[$(date)] Failed to cd to PROJECT_DIR ($PROJECT_DIR), skipping analysis" >> "$LOG_FILE"; rm -f "$analysis_file"; return; }
 
-  # Prevent observe.sh from recording this automated Haiku session as observations.
+  # Prevent observe.sh from recording this automated observer session as observations.
   # Pass prompt via -p flag instead of stdin redirect for Windows compatibility (#842).
   # prompt_content is already loaded in-memory so this no longer depends on the
   # mktemp absolute path continuing to resolve after cwd changes (#1296).
-  ECC_SKIP_OBSERVE=1 ECC_HOOK_PROFILE=minimal claude --model haiku --max-turns "$max_turns" --print \
+  # Model is configurable via ECC_OBSERVER_MODEL (defaults to haiku for cost efficiency);
+  # e.g. ECC_OBSERVER_MODEL=opus for higher-quality instinct extraction. Heavier models are
+  # slower — consider raising ECC_OBSERVER_TIMEOUT_SECONDS (default 120s) so the watchdog
+  # doesn't kill the analysis mid-run.
+  ECC_SKIP_OBSERVE=1 ECC_HOOK_PROFILE=minimal claude --model "${ECC_OBSERVER_MODEL:-haiku}" --max-turns "$max_turns" --print \
     --allowedTools "Read,Write" \
     -p "$prompt_content" >> "$LOG_FILE" 2>&1 &
   claude_pid=$!