feat: non-destructive lock recovery for pushed branches (Closes #440)

Adds structured issue-branch ownership parsing, wires it into lock adoption
and gitea_lock_issue validation, documents the restart recovery workflow, and
adds regression tests for adoption, durable create_pr resolution, and open-PR
blocking without remote branch deletion.

Built on keyed persistent lock store and own-branch adoption (#443 / #442).

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

docs/llm-workflow-runbooks.md

@@ -293,6 +293,28 @@ adoption rebinds the session when the issue's exact branch already exists (#442)
 `gitea_create_pr` resolves the durable keyed lock by session pointer or by
 matching `head` branch without unsafe manual seeding.
 
+### Non-destructive lock recovery after push (#440)
+
+When work is pushed but the in-memory MCP session lock is lost (server restart,
+crashed process, or stale session pointer):
+
+1. **Do not delete the remote branch.** Branch deletion is not a normal recovery
+   step and can destroy the only copy of unmerged work.
+2. **Re-run `gitea_lock_issue`** with the same `issue_number`, exact
+   `branch_name`, and active `branches/` worktree. Own-branch adoption
+   reacquires the lease when the remote branch is the caller's exact branch and
+   no open PR or competing same-issue branch exists.
+3. **Call `gitea_create_pr`** with the same `head` branch. The server resolves
+   the durable keyed lock file even when the session pointer was cleared at
+   restart.
+4. **Stop fail-closed** when another actor owns a competing branch, an open PR
+   already exists, or a live foreign lease blocks takeover — never adopt their
+   branch.
+
+Branch ownership uses structured evidence
+`(fix|feat|docs|chore)/issue-<n>-<desc>` — not broad substring matches on
+`issue-<n>`.
+
 Remote branches matching the issue number are also treated as active work unless
 the recovery review proves the branch is abandoned or superseded. Never delete
 or clean up a branch when it has an active lease, dirty worktree, open PR, or is