Feature: verifiable dreamer run progress (pending count + per-task status)

[canomogollon]

Short description

Surface verifiable progress for on-demand /ctx-dream runs so users can track backlog draining (e.g. unclassified memories) instead of relying on the end-of-run completion summary alone.

What problem does this solve?

The Dreamer runs a suite of tasks as child sessions, but the only feedback is a summary notification after the run completes. During long-running tasks there is no way to observe:

• how many items (memories/notes) remain to be processed in the current task;
• whether the run is making progress or stuck;
• which task is currently active.

Concretely, on a project with ~6.3k memories, map-memories and classify-memories abort with incomplete: N selected memories remain after the 20-minute default timeout_minutes. The message says N remains, but there is no increasing/decreasing signal across repeated on-demand runs, no per-task breakdown, and no percentage — so a user cannot tell whether repeated /ctx-dream invocations are converging or stuck on a prompt/issue (see closed bug #232 where classify-memories was silently using the wrong system prompt; a progress counter would have made that visible immediately).

Proposed solution

1. Persist per-task progress in the shared SQLite DB (a dream_progress table or columns on dream_runs): current task name, items processed, items remaining, started/finished timestamps, and status (pending/running/done/failed) for each task of the active run.
2. Expose it via a read-only surface: either a magic-context status CLI subcommand, a TUI sidebar section, or a Dashboard "Dream runs" progress view. The CLI is the most portable across OpenCode/Pi and trivially scriptable.
3. Emit progress during the run: the runner writes rows as each task iterates its selected items (e.g. every batch or every N items), so a watcher can poll and see the number decrease.

Alternatives considered

• Parsing the completion summary: insufficient — it only arrives after the run, carries no delta, and no partial info if a task aborts.
• Log scraping (/tmp/opencode/magic-context/magic-context.log): works but is fragile, harness-specific, and untyped.
• A status callback hook: viable for dashboards but leaves CLI users (who trigger /ctx-dream most) without a way to poll.

Area

Memory / historian / dreamer

Additional context

• The dreamer.tasks config already supports per-task timeout_minutes (raised to 90 for map-memories/classify-memories on our side); a progress view would let users right-size these timeouts with evidence.
• Related closed bug: "classify-memories" task uses my system prompt #232 — "classify-memories task uses my system prompt" (a progress counter surfaced the anomaly).
• Inspiration: CI runners show live job progress; the Dreamer is effectively a background job runner and would benefit from the same observability.
• We run a small monitoring script that queries memories WHERE classified_at IS NULL before/after each run to approximate progress; a first-class counter would replace this workaround.