fix(continuous-learning): bump observer MAX_TURNS default to 50 (#2035)

The observer's MAX_TURNS default of 20 was systematically insufficient
for the MAX_ANALYSIS_LINES default of 500. First-cycle analysis on a
fresh project consistently failed with "Reached max turns (20)", forcing
users to either raise ECC_OBSERVER_MAX_TURNS or lower
ECC_OBSERVER_MAX_ANALYSIS_LINES before the observer became useful.

Pair the defaults so the out-of-the-box experience succeeds: bump
MAX_TURNS to 50 (the value the reporter empirically settled on for the
500-line default). The safety floor (turns < 4 falls back to default) is
preserved.

Test asserting the default constant is updated alongside the source.

tests/hooks/hooks.test.js

@@ -2461,7 +2461,7 @@ async function runTests() {
       const observerLoopSource = fs.readFileSync(path.join(__dirname, '..', '..', 'skills', 'continuous-learning-v2', 'agents', 'observer-loop.sh'), 'utf8');
 
       assert.ok(observerLoopSource.includes('ECC_OBSERVER_MAX_TURNS'), 'observer-loop should allow max-turn overrides');
-      assert.ok(observerLoopSource.includes('max_turns="${ECC_OBSERVER_MAX_TURNS:-10}"'), 'observer-loop should default to 10 turns');
+      assert.ok(observerLoopSource.includes('max_turns="${ECC_OBSERVER_MAX_TURNS:-50}"'), 'observer-loop should default to 50 turns to pair with MAX_ANALYSIS_LINES=500 (#2035)');
       assert.ok(!observerLoopSource.includes('--max-turns 3'), 'observer-loop should not hardcode a 3-turn limit');
       assert.ok(observerLoopSource.includes('ECC_SKIP_OBSERVE=1'), 'observer-loop should suppress observe.sh for automated sessions');
       assert.ok(observerLoopSource.includes('ECC_HOOK_PROFILE=minimal'), 'observer-loop should run automated analysis with the minimal hook profile');