🦌 Add declarative input system for actions

[zdavison]

Summary

Introduces a declarative kadai:input frontmatter system that allows actions to declare their interactive inputs upfront. Declared inputs are collected as a form in the interactive menu, exposed as typed parameters in MCP tool calls, and automatically replayed by --rerun.

The .last-action file format is upgraded from a plain action ID string to a JSON record ({ actionId, inputs }) with backward-compatible parsing for old plain-text format. Sensitive inputs are filtered before saving so secrets are never persisted to disk.

Changes

• src/core/inputs.ts — new module with runWithStdinRecording, buildInjection, buildStdinStream, and filterSensitiveInputs helpers
• src/core/last-action.ts — upgraded .last-action format to JSON LastActionRecord; backward compat for old plain-string format
• src/core/commands.ts — handleRun supports recording and replay modes; handleRerun passes saved input values back through
• src/core/mcp.ts — declared inputs become typed Zod-validated MCP tool parameters
• src/types.ts — added ActionInput, InputValues, and LastActionRecord types
• src/cli.tsx — wires recording mode and sensitive input filtering into the interactive menu flow
• src/core/init-wizard.ts — documents input declaration syntax and injection behavior
• README.md — full documentation for kadai:input syntax, injection mechanics, and --rerun
• test/commands.test.ts, test/last-action.test.ts — updated tests for new record format and input handling
• test/fixtures/*/. kadai/.last-action — fixture files updated to JSON format

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Created by deer — review carefully.