Overhaul gt mol to match bd mol chemistry interface

## The Sling: Unified Work Dispatch

This issue tracks the overhaul of `gt molecule` to align with chemistry metaphor and introduce the **Universal Gas Town Propulsion Principle**.

### The Propulsion Principle

> **If you find something on your hook, YOU RUN IT.**

This is the one rule that drives all Gas Town agents.

### The Sling Operation

`gt sling <thing> <target> [options]` - unified command for spawn + assign + pin.

See: `gastown/mayor/rig/docs/sling-design.md`

### Implementation Tasks

| Issue | Title | Priority |
|-------|-------|----------|
| gt-4ev4 | Implement gt sling command | P1 |
| gt-uym5 | Implement gt mol status command | P1 |
| gt-i4kq | Update templates for Propulsion Principle | P1 |
| gt-7hor | Document the Propulsion Principle | P2 |

### Command Changes

| Old | New |
|-----|-----|
| `gt molecule instantiate` | `gt sling` |
| `gt molecule attach` | `gt sling --force` |
| `gt molecule detach` | `gt mol burn` |
| `gt molecule progress` | `gt mol status` |
| `gt molecule list` | `gt mol catalog` |
| `gt spawn --molecule` | `gt sling` |

### Acceptance Criteria

- [ ] `gt sling` works for protos, issues, and epics
- [ ] `gt mol status` shows hook state
- [ ] Templates updated for propulsion principle
- [ ] Old commands deprecated with warnings
- [ ] Documentation complete

Core sling work complete (gt-4ev4, gt-uym5, gt-7hor closed). gt-i4kq (template updates) remains open but is independent polish work.


Plugin: Plan-to-Epic converter

## Purpose

Help users create beads epics from various planning inputs.

## Inputs
- Markdown task lists
- GitHub issues
- Linear/Jira exports
- Free-form descriptions
- Existing beads epics

## Output
- Beads epic with properly structured children
- Dependencies set for wave ordering
- Priorities assigned
- Ready for `gt spawn --epic <id>`

## Implementation Options

### Option A: CLI Tool
```bash
gt plan import --from github --repo owner/repo --label batch-candidate
gt plan import --from markdown tasks.md
gt plan structure <epic-id>  # analyze and add dependencies
```

### Option B: Plugin Agent
A plugin at `<rig>/plugins/plan-oracle/` that:
- Receives planning requests via mail
- Analyzes scope and requirements
- Creates structured beads epic
- Sets dependencies based on analysis

### Option C: Interactive Mode
```bash
gt plan create
# Walks through questions, creates epic interactively
```

## Axiom

As stated: 'The Planning phase should end in the creation of a workable Beads plan.'

This plugin bridges the gap between human planning and machine-executable work.

## Priority

P2 - Nice to have for MVP. Manual epic creation works for now.

## Note

No "swarm IDs" - output is just a beads epic with children. Workers process it independently.


load-state

Read handoff bead and get nudge counts.

Needs: check-refinery

Parent gt-751s superseded by Christmas Ornament pattern


Merge: gt-ldk8

branch: polecat/nux
target: main
source_issue: gt-ldk8
rig: gastown


Refinery tmux status: show merge queue length

Add refinery-specific status line showing:
- MQ length (pending merges)
- Currently processing item (if any)
- Maybe: success/failure counts

Implement in runRefineryStatusLine() in internal/cmd/statusline.go

Implemented status line functions for witness and refinery


Merge: gt-rana.2

branch: polecat/nux
target: main
source_issue: gt-rana.2
rig: gastown

ORPHANED: Branch never pushed, worktree deleted


TODO: Check if issue is child of configured epic in Witness

witness/manager.go:688 has a TODO to filter issues by whether they're children of the configured epic. Currently this filter is skipped.

Implemented epic child filtering via isChildOfEpic() which checks if issue blocks the configured epic


VC Pattern Integration: Bring validated ideas to Gas Town

Analysis of ~/src/vc identified 6 validated patterns from the 2nd orchestrator attempt that map cleanly to Gas Town primitives. VC achieved 254 issues closed, 90.9% gate pass rate, and 24 successful missions.

Key insight: VC built ~4300 lines of Go for features that become ~65 lines of YAML + CLI flags in Gas Town's architecture.

Child tasks track each pattern to integrate.


mol-outpost-assign: Intelligent work routing to outposts

The federation design shows outposts.yaml with a static policy section. Simple preference ordering is fine as config, but intelligent work routing should be a molecule.

Current static approach:
```yaml
policy:
  default_preference: [local, gce-burst, cloudrun-burst]
```

Cases requiring cognition:
- "This is a long-running research task, route to VM not CloudRun"
- "This touches sensitive code, keep local"
- "These 5 issues are related, batch them to same outpost"
- "CloudRun cost is high today, prefer local even if slower"

## Molecule: outpost-assign
Intelligent work-to-outpost routing.

## Step: classify-work
Analyze the issue/work item:
- Expected duration (quick fix vs multi-hour)
- Resource requirements
- Sensitivity/security tier
- Related work (same epic?)

## Step: check-capacity
Query outpost status:
- Current load on each
- Cost accrued today
- Health status

## Step: select-outpost
Choose optimal outpost based on:
- Work classification
- Capacity/cost
- Policy constraints
Needs: classify-work, check-capacity

## Step: emit-assignment
Record decision in beads for audit.
Needs: select-outpost

## Notes
- This molecule is invoked by Mayor/Witness when spawning
- Simple cases can short-circuit to static policy
- Full analysis only for ambiguous cases


mol-polecat-work

Full polecat lifecycle from assignment to decommission.

This proto enables nondeterministic idempotence for polecat work.
A polecat that crashes after any step can restart, read its molecule state,
and continue from the last completed step. No work is lost.

Variables:
- gt-test123 - The source issue ID being worked on


gt rig info: Show detailed rig information

Add 'gt rig info <rig>' command to show detailed rig status.

Should show:
- Rig path and git URL
- Active polecats with status
- Refinery status
- Witness status
- Recent activity
- Beads summary (open issues count)


Swarm learning: Beads database locality gap

## PGT Bug (GGT Design Already Correct)

Mayor created issues in `~/ai/mayor/rigs/beads/.beads/` but polecats use `~/ai/beads/.beads/`. Different databases = polecats can't see Mayor's beads.

**GGT Fix**: architecture.md already specifies:
- All agents use BEADS_DIR pointing to rig-level `.beads/`
- Lines 116-143: Beads Configuration for Multi-Agent
- Lines 573-586: Rig-Level Beads via BEADS_DIR

This is a PGT implementation gap, not a design issue. GGT spawn must set BEADS_DIR correctly.


gt park command for parking molecules on external deps

Add `gt park` command for when polecat hits external dependency:

```bash
gt park --step=gt-mol.3 --waiting="beads:mol-run-assignee"
```

This command:
1. Adds blocked_by: external:beads:mol-run-assignee to the step
2. Clears assignee on the step
3. Clears assignee on molecule root
4. Sends handoff mail to self with context
5. Shuts down polecat session

The molecule enters "parked" state (derived: in_progress + no assignee + blocked step).

Part of cross-project dependency system.
See: docs/cross-project-deps.md

Depends on Beads: bd-om4a (external: blocked_by support)


bd pin command fails: invalid field for update: pinned

In beads v0.32.0, `bd pin <id>` fails with 'invalid field for update: pinned'. The pinned field exists in the schema but update logic doesn't handle it.

Repro:
```
bd create 'test issue'
bd pin <id>
# Error: invalid field for update: pinned
```

Expected: Issue should be pinned.

This blocks gt mail send --pinned from working.

Fixed by adding pinned to allowedUpdateFields


Merge: gt-caih

branch: polecat/furiosa
target: main
source_issue: gt-caih
rig: gastown


Immediate daemon notification on lifecycle request

When gt handoff sends a lifecycle request to the daemon (via bd mail send deacon/), the daemon only discovers it on its next heartbeat poll (every 5 min). Workers wait unnecessarily for retirement.

## Current Behavior
1. Worker runs gt handoff
2. Lifecycle mail sent to deacon/ via beads
3. Worker blocks waiting for retirement
4. Daemon heartbeat runs (up to 5 min later)
5. Daemon processes lifecycle request and kills session

## Expected Behavior
Lifecycle requests should be processed immediately, not on poll interval.

## Proposed Solutions

### Option A: SIGUSR1 Signal (simplest)
1. Add SIGUSR1 handler in daemon that calls ProcessLifecycleRequests()
2. gt handoff reads daemon.pid and sends SIGUSR1 after mail send

### Option B: Unix Socket
1. Daemon listens on ~/gt/daemon/lifecycle.sock
2. gt handoff connects and sends 'process' message

### Option C: Watchfile + fsnotify
1. gt handoff touches ~/gt/daemon/lifecycle.trigger
2. Daemon uses fsnotify to detect and process

Recommend Option A for simplicity.

## Affected Files
- internal/daemon/daemon.go - add signal handler
- internal/cmd/handoff.go - send signal after mail


Per-rig beads repo configuration

Add per-rig beads configuration to rig config schema.

## Config Schema

In each rig's config.json:

```json
{
  "version": 1,
  "name": "wyvern",
  "git_url": "https://github.com/steveyegge/wyvern",
  "beads": {
    "repo": "local",    // "local" | "<path>" | "<git-url>"
    "root": null,       // Override bd --root (optional)
    "prefix": "wyv"     // Issue prefix for this rig
  }
}
```

## Repo Options

| Value | Meaning | Use Case |
|-------|---------|----------|
| `"local"` | Use project's `.beads/` | Own projects, full commit access |
| `"<path>"` | Use beads at path | OSS contributions |
| `"<git-url>"` | Clone and use repo | Team shared beads |

## Environment Injection

When spawning polecats, Gas Town sets:
```bash
export BEADS_ROOT="<resolved-path>"
```

## Resolution Logic

```go
func ResolveBeadsRoot(rigConfig *RigConfig, rigPath string) (string, error) {
    beads := rigConfig.Beads
    switch {
    case beads.Root != "":
        return beads.Root, nil
    case beads.Repo == "local" || beads.Repo == "":
        return filepath.Join(rigPath, ".beads"), nil
    case strings.HasPrefix(beads.Repo, "/"):
        return beads.Repo, nil
    case strings.Contains(beads.Repo, "://"):
        return cloneAndResolve(beads.Repo)
    default:
        return filepath.Join(rigPath, beads.Repo), nil
    }
}
```

## Backwards Compatibility

If `beads` section missing, assume `"repo": "local"`.


Remove shell respawn loops from witness and deacon

Currently witness and deacon use shell loops (`while true; do claude; done`) to auto-respawn when Claude exits. This bypasses the proper lifecycle architecture.

## Current Behavior
- witness.go: ensureWitnessSession() wraps Claude in a shell loop
- deacon.go: runDeaconStart() wraps Claude in a shell loop
- When Claude exits, shell automatically restarts it

## Desired Behavior
- Agents should request lifecycle changes via LIFECYCLE mail to deacon
- Daemon processes lifecycle requests and handles restarts
- No shell loops - daemon and deacon's health-scan handle respawns

## Why Change
1. Shell loops bypass state verification (requesting_cycle flag)
2. Shell loops bypass handoff mail protocol
3. Shell loops make lifecycle tracking harder
4. Daemon already has infrastructure for this

## Migration
1. Remove shell loop from witness (daemon/deacon handles restart)
2. Remove shell loop from deacon (daemon handles restart via ensureDeaconRunning)
3. Verify daemon's health check properly restarts dead agents
4. Update templates if needed

## Risk
Low - we have gt witness restart and gt deacon restart as fallbacks

Removed shell respawn loops from witness and deacon. Daemon now properly detects dead Claude via pane command and restarts.