Implement the 4 empty function bodies in specs/ml/rl/ppo_critic.t27

[gHashTag]

Context

specs/ml/rl/ppo_critic.t27 declares module PpoCritic in 105 lines. 4 of its functions are declared with a body that holds no statement — a signature and a comment where the implementation belongs.

.t27 is the hand-authored source language. t27c compiles it out to C, Rust, Verilog and Zig. You are writing source, not compiler output, and not prose about an implementation.

Current state — re-run these yourself

$ cd /Users/playom/t27
$ ./target/release/t27c gen specs/ml/rl/ppo_critic.t27 2>&1 | grep -c 'not yet implemented'
4
$ ./target/release/t27c parse specs/ml/rl/ppo_critic.t27 2>&1 | grep -E '^(recovery-events|declarations-swallowed|lexer-discarded-chars):'
recovery-events: 0
declarations-swallowed: 0
lexer-discarded-chars: 0

Use ./target/release/t27c, not the t27c on PATH: the PATH build prints no parse metrics at all, so the grep above returns nothing and an empty result reads as a pass.

What to write

Keep every signature exactly as it is — the signature is the contract. Quoted verbatim from the file:

1. line 34 — fn forward(state: []const f32, params: []const f32, config: CriticConfig) -> f32
2. line 39 — fn compute_advantage(rewards: []f32, values: []f32, gamma: f32, lambda_: f32) -> []f32
3. line 44 — fn compute_returns(rewards: []f32, gamma: f32) -> []f32
4. line 49 — fn value_loss(predicted_values: []f32, target_values: []f32) -> f32

The file already has 0 test block(s). Add one for each function you implement; a body with nothing asserting on it is a claim, not a result.

Acceptance criteria

• 1. ./target/release/t27c gen specs/ml/rl/ppo_critic.t27 2>&1 | grep -c 'not yet implemented' prints 0
• 2. with criterion 1 satisfied, ./target/release/t27c parse specs/ml/rl/ppo_critic.t27 2>&1 | grep -E '^(recovery-events|declarations-swallowed|lexer-discarded-chars):' reports 0, 0 and 0
• 3. with criterion 1 satisfied, all 4 names above still exist: grep -cE '^\s*(pub )?fn (forward|compute_advantage|compute_returns|value_loss)\(' specs/ml/rl/ppo_critic.t27 prints 4
• 4. grep -c '^\s*test "' specs/ml/rl/ppo_critic.t27 prints at least 4 (today: 0)

Boundary

specs/ml/rl/ppo_critic.t27