fix(coord): make coord.sh's scope checks work on macOS and with glob scopes

[m-vawter]

coord.sh claim failed on macOS, and on any platform claim and review misbehaved around ## Files scopes. This PR has three fixes in coord.sh. The first two bring it in line with coord.ps1:

• claim, the macOS crash: the overlap check passed each Files entry to grep -x as a regex. The system grep (BSD grep 2.6.0-FreeBSD) rejects a glob like tests/** ("repetition-operator operand invalid"), and the claim aborted. Entries are now compared as exact strings (grep -qxF, like the PowerShell helper's -contains), and the lists are quoted so the shell never glob-expands an entry.
• claim, a silent exit everywhere: the loop ended on grep … && echo, so a final non-match left the command substitution at status 1, and set -e quietly exited claim whenever another open issue declared Files. It now uses if … fi.
• claim, body lines read as issues: the overlap loop read number<TAB>body line by line, so each line of a multi-line body was treated as an issue number ("invalid issue format" noise). A body line starting with digits would have been checked as that issue. It now emits just the number.
• review: PR paths are checked against Files entries the way coord.ps1 does it: a wildcard match either way, or a prefix match on the entry with trailing * and / trimmed. That's a new in_scope helper. Before, a substring test reported every file under a glob scope (like tests/**) as undeclared.

Verification

• bash -n coord.sh is clean.
• End to end on macOS (bash 3.2, BSD grep): this branch's helper claimed Ask Agent to Fix does nothing when Agent Chat is closed #92 for real ("Ask Agent to Fix does nothing when Agent Chat is closed #92 claimed by @m-vawter"), and it correctly refused an exact tests/** overlap with 0.1 Playwright end-to-end test of the core loop #79 before Ask Agent to Fix does nothing when Agent Chat is closed #92's Files were narrowed. It also marked 0.1 Playwright end-to-end test of the core loop #79 in-review against PR test: e2e Playwright test of the core loop (#79) #91, whose paths sit under tests/**, which main's review check rejects.
• in_scope passes 13/13 cases: tests/** covers tests/e2e/core-loop.spec.ts; README.md covers only itself; docs/ covers docs/x.md; app/features/os/** excludes app/features/apps/x.ts.
• Not run on Linux. The grep flags are POSIX and the helpers use only bash builtins. Once docs(coord): merge playbook rules into the coordinate skill #85's fixture harness has the gate work, these cases can move into it.

🤖 Generated with Claude Code

[xcjs]

Reviewed: in_scope() mirrors coord.ps1 wildcard semantics without regex/expansion (BSD+GNU safe), the claim clash loop no longer trips set -e on a non-match, and the review scope check uses in_scope. Fixes the exact macOS failures we saw with glob scope entries. Approving.