fix(beads): use hq- prefix for group/channel beads (town-level entities)

Groups and channels are town-level entities that span rigs, so they
should use the hq- prefix rather than gt- (rig-level).

Changes:
- GroupBeadID: gt-group- → hq-group-
- ChannelBeadID: gt-channel- → hq-channel-
- Add --force flag to bypass prefix validation (town beads may have
  mixed prefixes from test runs)
- Update tests and documentation

Also adds docs/beads-native-messaging.md documenting:
- New bead types (gt:group, gt:queue, gt:channel)
- CLI commands (gt mail group, gt mail channel)
- Address resolution logic
- Usage examples

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/beads-native-messaging.md

@@ -0,0 +1,226 @@
+# Beads-Native Messaging
+
+This document describes the beads-native messaging system, which extends Gas Town's mail system with first-class support for groups, queues, and channels backed by beads (Git-native storage).
+
+## Overview
+
+Beads-native messaging introduces three new bead types that integrate with the existing mail system:
+
+- **Groups** (`gt:group`) - Named distribution lists for multi-recipient delivery
+- **Queues** (`gt:queue`) - Work queues where workers claim items
+- **Channels** (`gt:channel`) - Pub/sub broadcast streams with retention policies
+
+All three are stored as beads, providing Git-native storage, audit trails, and replication.
+
+## Bead Types
+
+### Groups (`gt:group`)
+
+Groups are named collections of addresses used for mail distribution. Members can be:
+- Direct agent addresses (`gastown/crew/max`)
+- Wildcard patterns (`*/witness`, `gastown/*`)
+- Nested group names (groups can contain other groups)
+
+**ID Format:** `hq-group-<name>` (e.g., `hq-group-ops-team`)
+
+**Fields:**
+- `name` - Unique group name
+- `members` - Comma-separated list of addresses/patterns
+- `created_by` - Who created the group
+- `created_at` - ISO 8601 timestamp
+
+**Source:** `internal/beads/beads_group.go`
+
+### Queues (`gt:queue`)
+
+Queues are work queues where multiple workers can claim items. Messages sent to a queue are delivered once to a claiming worker.
+
+**ID Format:** `gt-q-<name>` or `hq-q-<name>` (town-level)
+
+**Fields:**
+- `name` - Queue name
+- `status` - `active`, `paused`, or `closed`
+- `max_concurrency` - Maximum concurrent workers (0 = unlimited)
+- `processing_order` - `fifo` or `priority`
+- `available_count`, `processing_count`, `completed_count`, `failed_count` - Queue statistics
+
+**Source:** `internal/beads/beads_queue.go`
+
+### Channels (`gt:channel`)
+
+Channels are pub/sub broadcast streams. Messages sent to a channel are retained according to the channel's retention policy and can be viewed by any subscriber.
+
+**ID Format:** `hq-channel-<name>` (e.g., `hq-channel-alerts`)
+
+**Fields:**
+- `name` - Unique channel name
+- `subscribers` - Comma-separated list of subscribed addresses
+- `status` - `active` or `closed`
+- `retention_count` - Number of messages to retain (0 = unlimited)
+- `retention_hours` - Hours to retain messages (0 = forever)
+- `created_by` - Who created the channel
+- `created_at` - ISO 8601 timestamp
+
+**Retention Enforcement:**
+- On-write cleanup: When a message is posted, old messages are pruned if over the limit
+- Patrol cleanup: Deacon patrol runs periodic cleanup with 10% buffer to avoid thrashing
+
+**Source:** `internal/beads/beads_channel.go`
+
+## CLI Commands
+
+### Group Commands
+
+```bash
+# List all groups
+gt mail group list [--json]
+
+# Show group details
+gt mail group show <name> [--json]
+
+# Create a group with members
+gt mail group create <name> [members...]
+gt mail group create ops-team gastown/witness gastown/crew/max
+gt mail group create ops-team --member gastown/witness --member gastown/crew/max
+
+# Add member to existing group
+gt mail group add <name> <member>
+
+# Remove member from group
+gt mail group remove <name> <member>
+
+# Delete a group
+gt mail group delete <name>
+```
+
+**Source:** `internal/cmd/mail_group.go`
+
+### Channel Commands
+
+```bash
+# List all channels
+gt mail channel [--json]
+gt mail channel list [--json]
+
+# View channel messages
+gt mail channel <name> [--json]
+gt mail channel show <name> [--json]
+
+# Create a channel with retention policy
+gt mail channel create <name> [--retain-count=N] [--retain-hours=N]
+gt mail channel create alerts --retain-count=100
+
+# Delete a channel
+gt mail channel delete <name>
+```
+
+**Source:** `internal/cmd/mail_channel.go`
+
+### Sending Messages
+
+The `gt mail send` command supports all address types through the address resolver:
+
+```bash
+# Send to agent (direct)
+gt mail send gastown/crew/max -s "Hello" -m "Message body"
+
+# Send to group (expands to all members)
+gt mail send ops-team -s "Alert" -m "Important message"
+gt mail send group:ops-team -s "Alert" -m "Explicit group syntax"
+
+# Send to queue (delivered to one claiming worker)
+gt mail send queue:build-queue -s "Job" -m "Build request"
+
+# Send to channel (broadcast, retained)
+gt mail send channel:alerts -s "Alert" -m "System alert"
+
+# Send to pattern (wildcards)
+gt mail send "*/witness" -s "Witness alert" -m "All witnesses"
+```
+
+**Source:** `internal/cmd/mail_send.go`
+
+## Address Resolution
+
+The address resolver (`internal/mail/resolve.go`) determines how to route messages based on the address format:
+
+### Resolution Order
+
+1. **Explicit prefix** - If address starts with `group:`, `queue:`, or `channel:`, use that type directly
+2. **Contains `/`** - Treat as agent address or pattern (direct delivery)
+3. **Starts with `@`** - Check for beads group, then fall back to built-in patterns
+4. **Name lookup** - Search in order: group → queue → channel
+
+### Address Formats
+
+| Format | Type | Example |
+|--------|------|---------|
+| `group:<name>` | Group | `group:ops-team` |
+| `queue:<name>` | Queue | `queue:build-queue` |
+| `channel:<name>` | Channel | `channel:alerts` |
+| `<town>/<role>/<name>` | Agent | `gastown/crew/max` |
+| `<town>/<role>` | Agent | `gastown/witness` |
+| `*/<role>` | Pattern | `*/witness` (all witnesses) |
+| `@<name>` | Group/Pattern | `@ops-team` |
+
+### Conflict Handling
+
+If a name matches multiple types (e.g., both a group and a channel named "alerts"), the resolver returns an error requiring an explicit prefix:
+
+```
+ambiguous address "alerts": matches multiple types. Use explicit prefix: group:alerts, channel:alerts
+```
+
+## Key Files
+
+| File | Description |
+|------|-------------|
+| `internal/beads/beads_group.go` | Group bead CRUD operations |
+| `internal/beads/beads_queue.go` | Queue bead CRUD operations |
+| `internal/beads/beads_channel.go` | Channel bead CRUD + retention |
+| `internal/mail/resolve.go` | Address resolution logic |
+| `internal/cmd/mail_group.go` | Group CLI commands |
+| `internal/cmd/mail_channel.go` | Channel CLI commands |
+| `internal/cmd/mail_send.go` | Send command with resolver |
+
+## Examples
+
+### Create a Team Distribution Group
+
+```bash
+# Create group
+gt mail group create dev-team gastown/crew/max gastown/crew/dennis
+
+# Add another member
+gt mail group add dev-team gastown/crew/george
+
+# Send to entire team
+gt mail send dev-team -s "Standup" -m "Daily standup in 5 minutes"
+```
+
+### Set Up a Build Alert Channel
+
+```bash
+# Create channel with retention
+gt mail channel create build-alerts --retain-count=50
+
+# Send build notifications
+gt mail send channel:build-alerts -s "Build #123 passed" -m "All tests green"
+
+# View channel history
+gt mail channel build-alerts
+```
+
+### Nested Groups
+
+```bash
+# Create base groups
+gt mail group create witnesses gastown/witness ranchero/witness
+gt mail group create crew gastown/crew/max gastown/crew/dennis
+
+# Create umbrella group that includes other groups
+gt mail group create all-agents witnesses crew deacon/
+
+# Send to everyone
+gt mail send all-agents -s "Town meeting" -m "All hands meeting at noon"
+```

internal/beads/beads_channel.go

@@ -127,15 +127,15 @@ func ParseChannelFields(description string) *ChannelFields {
 	return fields
 }
 
-// ChannelBeadID returns the channel bead ID for a given channel name.
+// ChannelBeadID returns the bead ID for a channel name.
-// Format: hq-channel-<name> for town-level channels (default).
+// Format: hq-channel-<name> (town-level, channels span rigs)
-// Town-level channels are stored in the shared beads database.
 func ChannelBeadID(name string) string {
 	return "hq-channel-" + name
 }
 
 // CreateChannelBead creates a channel bead for pub/sub messaging.
-// The ID format is: hq-channel-<name> (e.g., hq-channel-alerts) for town-level.
+// The ID format is: hq-channel-<name> (e.g., hq-channel-alerts)
+// Channels are town-level entities (hq- prefix) because they span rigs.
 // The created_by field is populated from BD_ACTOR env var for provenance tracking.
 func (b *Beads) CreateChannelBead(name string, subscribers []string, createdBy string) (*Issue, error) {
 	id := ChannelBeadID(name)
@@ -156,6 +156,7 @@ func (b *Beads) CreateChannelBead(name string, subscribers []string, createdBy s
 		"--description=" + description,
 		"--type=task", // Channels use task type with gt:channel label
 		"--labels=gt:channel",
+		"--force", // Override prefix check (town beads may have mixed prefixes)
 	}
 
 	// Default actor from BD_ACTOR env var for provenance tracking

internal/beads/beads_group.go

@@ -97,13 +97,14 @@ func ParseGroupFields(description string) *GroupFields {
 }
 
 // GroupBeadID returns the bead ID for a group name.
-// Format: gt-group-<name>
+// Format: hq-group-<name> (town-level, groups span rigs)
 func GroupBeadID(name string) string {
-	return "gt-group-" + name
+	return "hq-group-" + name
 }
 
 // CreateGroupBead creates a group bead for mail distribution.
-// The ID format is: gt-group-<name> (e.g., gt-group-ops-team)
+// The ID format is: hq-group-<name> (e.g., hq-group-ops-team)
+// Groups are town-level entities (hq- prefix) because they span rigs.
 // The created_by field is populated from BD_ACTOR env var for provenance tracking.
 func (b *Beads) CreateGroupBead(name string, members []string, createdBy string) (*Issue, error) {
 	id := GroupBeadID(name)
@@ -123,6 +124,7 @@ func (b *Beads) CreateGroupBead(name string, members []string, createdBy string)
 		"--description=" + description,
 		"--type=task", // Groups use task type with gt:group label
 		"--labels=gt:group",
+		"--force", // Override prefix check (town beads may have mixed prefixes)
 	}
 
 	// Default actor from BD_ACTOR env var for provenance tracking

internal/beads/beads_group_test.go

@@ -163,9 +163,9 @@ func TestGroupBeadID(t *testing.T) {
 		name string
 		want string
 	}{
-		{"ops-team", "gt-group-ops-team"},
+		{"ops-team", "hq-group-ops-team"},
-		{"all", "gt-group-all"},
+		{"all", "hq-group-all"},
-		{"crew-leads", "gt-group-crew-leads"},
+		{"crew-leads", "hq-group-crew-leads"},
 	}
 
 	for _, tt := range tests {