feat: expose generated Rite CLI reads

[shivros]

Summary

• expose the generated list-sources, list-handlers, and get-handler commands directly from rite-cli
• route reads through the existing execute_operation dispatcher with JSON output/error contracts
• preserve both explicit serve and no-subcommand server invocation; document CLI/MCP usage

Verification

• cargo fmt --all -- --check
• cargo build --all-targets
• cargo test --all-targets
• cargo clippy --all-targets -- -D warnings
• CLI read, not-found, invalid-config JSON, and explicit/default serve smoke checks

Closes COD-464.

[shivros]

🤖 Automated Review Panel

Reviewer A — gpt-5.6-terra

Resolved finding: generated-read validation errors initially mixed timestamped diagnostics with JSON. Read-mode config validation now suppresses diagnostics and returns only deterministic {"error":"invalid Rite configuration"} with exit 1. Reviewer also verified workspace tests, Clippy, codegen check, generated command paths, and explicit/default serve behavior.

Reviewer B — independent review

APPROVE. Confirmed flattened GeneratedCommand keeps the generated API contract authoritative, read commands use the shared dispatcher, the placeholder secret is not emitted or used for webhook ingress, and global CLI arguments preserve server compatibility.

Both initial review findings (manual generated-command duplication and non-JSON setup errors) were addressed before this PR was opened.

[shivros]

Auto-Merge Gate

Confidence: 0.93

The generated list-sources, list-handlers, and get-handler CLI reads are wired through Rite's existing execute_operation dispatcher, preserving the contract as the sole operation definition. The default and explicit serve paths remain compatible, with deterministic JSON output/error behavior documented.

Observed checks: GitHub Actions test completed successfully. Independent local verification also passed: cargo test --all-targets (14 tests).

Scope reviewed: four coherent files (CLI wiring, dependencies/lockfile, README); no deployment, credential, destructive, or manual-review scope was found.