t27b: carry std.ArrayList(T) and std.StringHashMap(V) that are never opened (type (generic)) #8701

Problem

t27b refuses two specs that the reference (t27c gen + zig test) passes, both as type (generic) (docs/reports/t27b_expectations.json):

• specs/port/trinity/src/tri-api/claude_md.t27: parts: *std.ArrayList(u8) parameters of fns no test calls (line 15, line 21).
• specs/port/trinity/src/phi-engine/vibeec_original/bogatyrs_registry.t27: a struct field plugins: std.StringHashMap(PluginEntry), set to undefined and never read (line 14); every test then cascades as ExprCall(rejected fn).

What Zig does

Neither spec opens the container: no method call, no field read. Zig instantiates the generic with its argument, which must name a type, and the struct it returns has a size that does not depend on the argument. Measured with zig 0.16.0 on the t27c lab, Debug build: @sizeOf(std.ArrayList(T)) is 24, @sizeOf(std.StringHashMap(V)) is 40, both aligned to 8.

Plan

In line with #8696 (see #7917), which carries a std.mem.Allocator as an opaque value: t27b carries std.ArrayList(T) and std.StringHashMap(V) as structs with no fields and Zig's Debug layout, after naming the argument as a pointee. Calls and field reads keep their refusals by name. Any other generic stays type (generic). The decision lives in specs/tri/t27b/opaque_plan.t27; no real generics are needed.

Acceptance

• Both specs pass t27b test <spec> --check with runtime asserts, or move on to their next blocker; the ledger rows follow.
• The t27b lab corpus moves only those two files.
• Net hand lines <= 0 (check_budget).

User Scenarios

• Given a spec specs/port/trinity/src/tri-api/claude_md.t27 with parts: *std.ArrayList(u8) parameters on uncalled fns, When running t27b test <spec> --check, Then the spec passes with runtime asserts instead of refusing type (generic).
• Given a spec specs/port/trinity/src/phi-engine/vibeec_original/bogatyrs_registry.t27 with a struct field plugins: std.StringHashMap(PluginEntry) set to undefined and never read, When running t27b test <spec> --check, Then the spec passes with runtime asserts instead of cascading ExprCall(rejected fn).

Requirements

• FR-001: t27b MUST carry std.ArrayList(T) as an opaque struct of size 24, alignment 8, after naming T as a pointee.
• FR-002: t27b MUST carry std.StringHashMap(V) as an opaque struct of size 40, alignment 8, after naming V as a pointee.
• FR-003: The opaque layout decision MUST be recorded in specs/tri/t27b/opaque_plan.t27 without introducing real generics.
• FR-004: Calls and field reads on these carried types MUST keep their existing refusals by name.
• FR-005: The ledger docs/reports/t27b_expectations.json MUST update only the two cited spec rows.
• FR-006: Net hand lines MUST be <= 0 as verified by check_budget.

Success Criteria

• t27b test specs/port/trinity/src/tri-api/claude_md.t27 --check exits 0 with runtime asserts.
• t27b test specs/port/trinity/src/phi-engine/vibeec_original/bogatyrs_registry.t27 --check exits 0 with runtime asserts.
• docs/reports/t27b_expectations.json shows only the two cited spec rows changed from type (generic) refusal to pass.
• check_budget reports net hand lines <= 0.

Boundary

• specs/port/trinity/src/tri-api/claude_md.t27
• specs/port/trinity/src/phi-engine/vibeec_original/bogatyrs_registry.t27
• specs/tri/t27b/opaque_plan.t27
• docs/reports/t27b_expectations.json
• scripts/tri_loop/t27b.py