fix: don't pin dashboard to a non-orchestrator session

[jgnagy]

Problem

The dashboard's left Registry stays stuck on "Spawning delegates…" showing 0 delegates, even though delegate messages stream onto the wall and delegate sub-agent sessions clearly exist in sessions.db.

The registry and the wall are two independent data sources:

• The wall (messages) is read from the flat GOOSE_GTWALL_FILE — works regardless of session resolution.
• The delegate registry is built by scanning the parent (orchestrator) session's messages for Task <id> started in background (CHILD_PATTERN). If the dashboard pins the wrong parent session, find_children() matches nothing → 0 delegates forever.

Two bugs, plus a latent multi-instance hazard:

1. dashboard → resolve_session() trusted AGENT_SESSION_ID unconditionally and passed it as --session, which makes goosetown-ui skip its own discovery. goose exports a terminal session id into shell subprocesses, so launching the dashboard from a goose shell pins that terminal session — which has no delegates. (Observed: dashboard launched with --session 20260525_4, a session_type='terminal' session with zero "started in background" messages, while the real orchestrator was 20260601_3.)
2. scripts/goosetown-ui → sessions_tree_watcher() reads parent_id once and never re-resolves, so any wrong/early pin is permanent.
3. Multi-instance: every goosetown on the machine shares one sessions.db, and sessions carry no instance/wall identifier. "Most recent delegate-bearing user session" picks whichever orchestrator was touched last — so with concurrent instances, dashboard A could resolve (or self-heal) onto orchestrator B.

Fix

Commit 1 — don't pin a non-orchestrator session

• resolve_session(): only trust AGENT_SESSION_ID when it actually has delegate activity; otherwise discover a delegate-bearing session. Adds session_has_delegates().
• sessions_tree_watcher(): re-resolve when the pinned parent has 0 children, adopting a candidate only if it actually has children (no thrash).

Commit 2 — scope resolution to the instance's wall (multi-instance safe)

• The wall is the per-instance anchor: an instance's wall lists its delegates' gtwall IDs (senders), and the orchestrator's spawn messages declare those same IDs (already parsed by build_sender_session_map). Matching them uniquely identifies this instance's orchestrator.
• goosetown-ui: adds scoped_parent_session(cur, senders) (most sender-overlap wins, ties → most recent, else None). find_parent_session() prefers it; main() lets a positive wall-scoped match override an explicit --session; the self-heal re-resolves on 0 children or when the current parent's delegates don't match the wall's senders (wrong instance), using only the scoped lookup — so it can adopt this instance's orchestrator and never another's.
• dashboard: resolve_session() prefers a delegate-bearing user session that references this wall (WALL_ID, already sanitized to [A-Za-z0-9_-]) before the generic query. Best-effort hint; goosetown-ui is authoritative.

Verification

Real sessions.db that exhibited the bug:

resolve_session  AGENT_SESSION_ID=20260525_4 (terminal), WALL_ID set/unset  -> 20260601_3
self-heal: pinned terminal session (0 children) -> re-resolves to orchestrator
no-thrash: a correct parent with children is left untouched

Synthetic two-instance sessions.db (orchestrator A → researcher-alpha; orchestrator B → researcher-beta, more recently updated):

scoped(A wall senders)              -> orchestrator A   (not B, despite B newer)
scoped(B wall senders)              -> orchestrator B
find_parent_session(A wall file)    -> orchestrator A
find_parent_session(B wall file)    -> orchestrator B
scoped(no delegate senders)         -> None             (never a cross-instance guess)
bash resolve_session WALL_ID=BBB, AGENT_SESSION_ID=A_orch -> B   (wall overrides env)

• bash -n dashboard and python3 -m py_compile scripts/goosetown-ui pass.
• tests/test_dashboard.sh: 4 passed, 0 failed (the pre-existing tmpfile: unbound variable teardown wart is unrelated).

Known limitation

If two concurrent instances spawn delegates with identical gtwall IDs, the most-overlap-then-most-recent tiebreak may still pick the wrong one. Walls/ports/screens remain fully isolated per instance regardless.

🤖 Generated with Claude Code

[zazer0]

Hi, is this project abandoned? (just confirming before I spend time contributing)

@tlongwell-block
@maxamillion
@balcsida

[balcsida]

@zazer0 I'm an outside contributor

[tlongwell-block]

Hi, @zazer0 👋

The goose team was working on getting some of the nice idea in goosetown directly into goose, like the nest and better subagent communication. cc @DOsinga here

Let me take a look at this PR in a bit

[tlongwell-block]

lgtm. Thanks @jgnagy 👍