T27 OS: clear the three red gates on the petal branch (t27b ledger, duplicate bodies, Verilog widths) #11024

Refs #10782.

Background: the T27 OS window branch feat/t27os-petal-menu (PR #10783) is red on three gates that are not caused by the PRs stacked on it. The ledger is docs/reports/t27b_expectations.json. Rows for the removed pty_client, pty_server and pty_sys externs were already dropped in PR #10977. Edit the ledger by regenerating it with t27b, never by hand. Only .t27: no code in any other language, not even scratch probes or a loader; see skill only-t27. Builds and tests run on the Railway lab.

Boundary

• docs/reports/t27b_expectations.json
• specs/t27os/glass_window.t27
• specs/t27os/doctor.t27

User Scenarios

• Given the petal branch, when t27b-native-ratchet runs, then it reports UNLISTED 0 and STALE 0 for specs/t27os/*.
• Given the petal branch, when the duplicate-bodies gate runs, then none of clamp01 and flag_bit is reported, because their bodies in specs/t27os/ are unique.
• Given the petal branch, when the Verilog widths gate runs, then specs/t27os/glass_window.t27 is not reported as NEW over its width limit.

Requirements

• FR-001: The t27b ledger MUST list every spec under specs/t27os/ and no spec that no longer exists.
• FR-002: The functions clamp01 and flag_bit in specs/t27os/ MUST NOT share a body with another function in specs/; reuse a single home through use.
• FR-003: The wide buffer in specs/t27os/glass_window.t27 MUST be split or narrowed so the Verilog width gate no longer reports 1535999.

Success Criteria

• grep -c "specs/t27os/" docs/reports/t27b_expectations.json prints at least 21
• grep -rl "fn flag_bit" specs | wc -l prints 1
• grep -rl "fn clamp01" specs/t27os | wc -l prints 1
• t27c test-report specs/t27os/glass_window.t27 does not print FAIL