CANP-WP-0002 T04: eval schema, render checks and output criteria

`evals/` was a reserved path holding unvalidated blobs: section 12 named the
directory and gave an illustrative snippet, but nothing was specified, so no
tool could act on an eval file.

Every eval file must now declare a `schema`, and CPF defines exactly one —
`canned-prompts/eval-rubric/v0.1`. Unrecognized schemas stay legal and are
skipped rather than rejected, so the format gains something actionable without
becoming an evaluation language, which remains a non-goal.

The schema splits along the same seam as T01 and T03. Render checks
(`contains`, `not_contains`, `resolves_all`) assert properties of the rendered
prompt text, need no model, and are therefore run by the reference CLI. Output
criteria describe a good result and are declared but not run, because judging
them requires a model. That division is now the format's consistent answer to
"deterministic locally, or not".

An eval references a fixture already declared in the manifest's `examples`
rather than carrying its own copy, so an example that is also an eval fixture
stays honest — both break together.

An eval declares assessment and must not record outcomes. Results are run
evidence and live outside the immutable package, per INTENT.md and section 17.

Spec: 12 rewritten with 12.1, 18 (rules 17-18), 21 (`eval` verb).

Reference CLI: read_eval, validate_eval, load_example_values,
run_render_checks, cmd_eval; a failed render check exits non-zero.
Tests 42 -> 51.

examples/pqrst-estimate/evals/quality.yaml is a real eval with four render
checks and four output criteria, and it passes.

Fixes a latent bug reaching a fixture exposed: coerce_value assumed every
value was a command-line string, so a YAML fixture carrying a real type
(include_rationale: true) crashed on .lower(). Typed values are now validated
but not re-parsed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bjefh8NUiEiahN4JLwoSKM

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 388925@bnt-lap001
Assistant-Session: 3507023f-e0fd-4a1e-9d90-a0d4217d1502

examples/pqrst-estimate/evals/quality.yaml

@@ -0,0 +1,19 @@
+schema: canned-prompts/eval-rubric/v0.1
+name: pqrst-estimate-quality
+description: >
+  The prompt asks for a post-session audit with a hard 100% constraint, and the
+  resulting estimate respects both.
+example: examples/basic.yaml
+
+render:
+  - contains: "must sum to exactly 100%"
+  - contains: "post-session audit, not a planning estimate"
+  - not_contains: "{{"
+  - resolves_all: true
+
+output:
+  criteria:
+    - The five percentages sum to exactly 100%.
+    - Categories are not silently renamed, merged, or dropped.
+    - Effort is attributed from evidence in the session summary, not invented.
+    - The estimate reads as an audit of work done, not a plan for work ahead.

examples/pqrst-estimate/prompt.yaml

@@ -49,3 +49,5 @@ provenance:
   author: canned-prompts seed
 examples:
 - examples/basic.yaml
+evals:
+- evals/quality.yaml