Fix --all-branches and --branch filtering from worktrees

[wesm]

Summary

• Fix roborev fix --all-branches and --branch <name> not discovering jobs from other branches when run from a git worktree — filterReachableJobs was called with an empty branch override, causing it to filter by the worktree's branch instead of the requested branch
• Deprecate --open and --unaddressed flags — open job discovery is now the default behavior when no positional job IDs are provided; both flags are hidden and silently ignored for backwards compatibility
• Thread allBranches and explicitBranch through runFixOpen/runFixBatch to distinguish three filtering modes: default (commit-graph reachability), --branch X (branch-field matching for cross-branch fixing), and --all-branches (skip filtering)
• Add tests for all-branches discovery, explicit branch filtering, and worktree reachability

[roborev-ci]

roborev: Combined Review (55c8b51)

Verdict: The PR updates branch-selection semantics for fix flows, but introduces high-severity regressions in commit reachability filtering and list
mode branch handling.

High

• Location: cmd/roborev/fix.go:463, cmd/roborev/fix.go:980
  Problem: Mutating fix paths no longer enforce commit-graph reachability when discovery is driven by
  --branch or --all-branches. --branch now switches to branch-name matching, and --all-branches skips filterReachableJobs entirely, meaning roborev fix or roborev fix --batch can mistakenly apply findings from rebased-away commits or different branch/
  worktrees to the current checkout.
  Fix: Retain reachability filtering for mutating flows. Treat --branch/--all-branches strictly as query selectors unless the command can first resolve and operate in the matching worktree. Add regression coverage for stale same-branch SHA jobs and cross-worktree
  branch jobs.

• Location: cmd/roborev/fix.go (around line 159, in RunE's --list block and runFixList signature)
  Problem: runFixList was not updated to accept the allBranches boolean
  . Running roborev fix --list --all-branches calls runFixList with an empty string for the branch, which then calls filterReachableJobs with branchOverride="", falling back to commit-graph reachability filtering and incorrectly hiding jobs from other branches.
  **Fix
  **: Update runFixList's signature to accept allBranches (matching runFixOpen and runFixBatch) and conditionally skip filterReachableJobs when allBranches is true.

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Synthesized from 3 reviews (agents: codex, gemini | types: default, security)

[wesm]

Non-issues in practice. Merging