chore: merge main (v0.7.2), resolve conflicts, bump to v0.7.3

Merge origin/main which brought proactive skill suggestions, journey-stage
E2E tests, and retro timezone/midnight fixes. Resolve VERSION (0.7.3),
CHANGELOG (our entry above 0.7.2), and gen-skill-docs.ts (keep both
telemetry line and proactive config). Regenerate all 21 SKILL.md files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

plan-eng-review/SKILL.md

@@ -6,6 +6,8 @@ description: |
   data flow, diagrams, edge cases, test coverage, performance. Walks through
   issues interactively with opinionated recommendations. Use when asked to
   "review the architecture", "engineering review", or "lock in the plan".
+  Proactively suggest when the user has a plan or design doc and is about to
+  start coding — to catch architecture issues before implementation.
 allowed-tools:
   - Read
   - Write
@@ -33,8 +35,13 @@ _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no
 echo "LAKE_INTRO: $_LAKE_SEEN"
 mkdir -p ~/.gstack/analytics
 echo '{"skill":"plan-eng-review","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","repo":"'$(basename "$(git rev-parse --show-toplevel 2>/dev/null)" 2>/dev/null || echo "unknown")'"}'  >> ~/.gstack/analytics/skill-usage.jsonl 2>/dev/null || true
+_PROACTIVE=$(~/.claude/skills/gstack/bin/gstack-config get proactive 2>/dev/null || echo "true")
+echo "PROACTIVE: $_PROACTIVE"
 ```
 
+If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills — only invoke
+them when the user explicitly asks. The user opted out of proactive suggestions.
+
 If output shows `UPGRADE_AVAILABLE <old> <new>`: read `~/.claude/skills/gstack/gstack-upgrade/SKILL.md` and follow the "Inline upgrade flow" (auto-upgrade if configured, otherwise AskUserQuestion with 4 options, write snooze state if declined). If `JUST_UPGRADED <from> <to>`: tell user "Running gstack v{to} (just updated!)" and continue.
 
 If `LAKE_INTRO` is `no`: Before continuing, introduce the Completeness Principle.

plan-eng-review/SKILL.md.tmpl

@@ -6,6 +6,8 @@ description: |
   data flow, diagrams, edge cases, test coverage, performance. Walks through
   issues interactively with opinionated recommendations. Use when asked to
   "review the architecture", "engineering review", or "lock in the plan".
+  Proactively suggest when the user has a plan or design doc and is about to
+  start coding — to catch architecture issues before implementation.
 allowed-tools:
   - Read
   - Write