Rebrand to IronClaw with security-first mission

Renamed project from "near-agent" to "ironclaw" throughout the codebase.
Updated documentation to emphasize the core philosophy:
- Your data stays yours (local, encrypted, no telemetry)
- Self-expanding capabilities (build tools on the fly)
- Defense in depth (WASM sandbox, prompt injection defense)
- Always on user's side

Key changes:
- Package name: near-agent -> ironclaw
- Config paths: ~/.near-agent/ -> ~/.ironclaw/
- Database name in docs: near_agent -> ironclaw
- CLI binary: near-agent -> ironclaw
- Log filters: RUST_LOG=near_agent -> RUST_LOG=ironclaw
- All user-facing strings (welcome messages, help text, etc.)

Preserved for compatibility:
- HKDF salt "near-agent-secrets-v1" (changing would break existing secrets)
- WIT interface names (near::agent::*)
- NEAR AI provider config (NEARAI_* env vars)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

channels-src/slack/Cargo.toml

@@ -2,7 +2,7 @@
 name = "slack-channel"
 version = "0.1.0"
 edition = "2021"
-description = "Slack Events API channel for NEAR Agent"
+description = "Slack Events API channel for IronClaw"
 license = "MIT OR Apache-2.0"
 
 [lib]