refactor: make all scripts multi-project via env vars

Replace hardcoded harb references across the entire codebase:
- HARB_REPO_ROOT → PROJECT_REPO_ROOT (with deprecated alias)
- Derive PROJECT_NAME from CODEBERG_REPO slug
- Add PRIMARY_BRANCH (master/main), WOODPECKER_REPO_ID env vars
- Parameterize worktree prefixes, docker container names, branch refs
- Genericize agent prompts (gardener, factory supervisor)
- Update best-practices docs to use $-vars, prefix harb lessons

All project-specific values now flow from .env → lib/env.sh → scripts.
Backward-compatible: existing harb setups work without .env changes.

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

factory/best-practices/memory.md

@@ -7,12 +7,12 @@
 ## Safe Fixes (no permission needed)
 - Kill stale `claude` processes (>3h old): `pgrep -f "claude" --older 10800 | xargs kill`
 - Drop filesystem caches: `sync && echo 3 | sudo tee /proc/sys/vm/drop_caches`
-- Restart bloated Anvil: `sudo docker restart harb-anvil-1` (grows to 12GB+ over hours)
+- Restart bloated Anvil: `sudo docker restart ${PROJECT_NAME}-anvil-1` (grows to 12GB+ over hours)
 - Kill orphan node processes from dead worktrees
 
 ## Dangerous (escalate)
 - `docker system prune -a --volumes` — kills CI images, hours to rebuild
-- Stopping harb stack containers — breaks dev environment
+- Stopping project stack containers — breaks dev environment
 - OOM that survives all safe fixes — needs human decision on what to kill
 
 ## Known Memory Hogs
@@ -26,4 +26,4 @@
 ## Lessons Learned
 - After killing processes, always `sync && echo 3 | sudo tee /proc/sys/vm/drop_caches`
 - Swap doesn't drain from dropping caches alone — it's actual paged-out process memory
-- Running CI + full harb stack = 14+ containers on 8GB. Only one pipeline at a time.
+- Running CI + full project stack = 14+ containers on 8GB. Only one pipeline at a time.