P1: add optional read/find range and pagination arguments

[novelKR]

Summary

• Add optional offset/limit on MCP read (byte window) and find (sorted path page). Omitted arguments keep the first 1 MiB / 10_000-path window.
• Keep per-call caps and whole-file version hashes. truncated means more remains; continue read at offset + byte_count.
• Advertise execution.files.capabilities (read_range, find_pagination, read_max_bytes, find_max_paths). Bump UDS WIRE_PROTOCOL to 6. Explicit limit 0 or above the cap is OUTPUT_LIMIT.

Test plan

• cargo test -p codespace-domain --offline
• cargo test -p codespace-runner --lib --offline
• cargo test -p codespace-runner --offline --test fs_watch --test uds_runner
• cargo test -p codespace-server --offline --lib
• cargo test -p codespace-server --offline --test read_find --test protocol_compat --test process
• python3 scripts/check_docs.py check
• CI on this PR

Out of scope

• Line-based range, cursor tokens, lifting the 1 MiB / 10_000 caps
• Partial seek I/O (response windowing only)
• Resource queue scheduler, durable process recovery

Made with Cursor