docs(release): v0.25.0 notes — add historian-stall fix headline + /ctx-embed

Co-authored-by: Alfonso [Magic Context] <288211368+alfonso-magic-context@users.noreply.github.com>

Author: ualtinok

.alfonso/release-notes/v0.25.0.md

@@ -1,6 +1,6 @@
 # v0.25.0
 
-Makes context reduction more automatic and fully reversible: old tool output is now reclaimed without you asking, anything that gets dropped can be recovered in full, and the agent is better at trimming spent output on its own. Also fixes a broken Pi command, missing embeddings on Windows/Desktop, runaway background agents, and several prompt-cache busts.
+Makes context reduction more automatic and fully reversible: old tool output is now reclaimed without you asking, anything that gets dropped can be recovered in full, and the agent is better at trimming spent output on its own. Also fixes a case where history summarization could silently stall, a broken Pi command, missing embeddings on Windows/Desktop, runaway background agents, and several prompt-cache busts.
 
 ## New: automatic reclaim of old tool output
 
@@ -23,6 +23,7 @@ The `ctx_reduce` description framed dropping as immediate and irreversible (`dro
 
 ## Fixes
 
+- **History summarization could silently stall.** If a tool call was interrupted (an aborted run, a crash) and left dangling without a result, the summarizer's boundary logic could refuse to advance past it — so a session would stop compacting and just grow, with no error, until it ran out of room. The only recovery was rebuilding the session. The boundary now skips a stale, never-completing tool call instead of getting stuck behind it. This affected sessions on 0.23.0–0.24.1.
 - **Pi: `/ctx-dream` was broken (#151).** It failed with `Unknown named parameter '0'` on Pi and Desktop. A single database call used an array-bind form that works under one SQLite engine but not the other; it's fixed, and the engine layer now normalizes this so the whole class can't recur.
 - **Pi / Desktop: local embeddings could fail to load (#128).** When the local embedding runtime is missing or broken (a common Windows case), Magic Context now degrades cleanly with one clear message instead of repeated cryptic errors, and `doctor` detects and reports it.
 - **Runaway background agents (#154, #152).** A weak or local model could get a background agent (history summarizer, dreamer) stuck in an endless tool-call loop that survived even cancelling — only a full restart stopped it. Background agents now have a hard step cap and are force-stopped on timeout.
@@ -33,6 +34,7 @@ The `ctx_reduce` description framed dropping as immediate and irreversible (`dro
 
 ## Also in this release
 
+- **`/ctx-embed` — see and control history embedding.** Run `/ctx-embed` for a breakdown of what's embedded for the session (model, and how many compartments / memories / commits are covered), and `/ctx-embed start` / `pause` to control the backfill. A session's missing history now also backfills automatically in the background, so older discussion becomes semantically searchable via `ctx_search` without a manual step. (Replaces `/ctx-embed-history`.)
 - **Background agents can now manage their own context.** `ctx_reduce` and the context-pressure nudges are available to subagents, so long-running background work stays lean (paired with the automatic reclaim above).
 - **Pasted noise in your messages can be dropped.** A large pasted block (logs, data dumps) inside one of your messages can now be reduced once it's been processed — your instructions are always preserved, and the content stays searchable via `ctx_search`.
 - **Internal hardening:** added cross-engine SQLite test coverage to CI and brought the Pi `doctor` embedding check to parity with OpenCode.