Sync MCP surface to SPEC §7 process model

Rename list_children/read_output/kill/send_message_to to their SPEC §7
process_id-shaped names; drop report_to_parent (direction inferred by
send_message) and policy_check (replaced by per-project trust gating).
Add the SPEC's missing tools: start_process, restart_process,
close_process, rename_process, select_process, get_process_status,
get_project_status, get_process_raw_output, search_output,
get_process_ports, whoami, help.

Process model now distinguishes agent/terminal/command kinds with
opaque p_<6hex> IDs. Command entries are session-persistent so they
survive PTY exit and can be Restart'd. Status enum gains starting and
stopped. screen_version, port detection, and bracketed-paste send_input
land alongside.

Trust gating (internal/trust) replaces the regex policy: command-preset
spawns return needs_trust on first use; the user confirms in a
status-line modal and the grant persists to
\$XDG_DATA_HOME/patterm/projects/<key>/trust.json.

Tests cover send_message direction inference (parent↔child, sibling
rejection, nil caller paths) and trust grant persistence across reopen.

internal/vt/ghostty_nocgo.go

@@ -17,6 +17,7 @@ func NewGhosttyEmulator(cols, rows uint16) (*GhosttyEmulator, error) {
 
 func (e *GhosttyEmulator) Write(p []byte) (int, error)    { return 0, errStub }
 func (e *GhosttyEmulator) Resize(cols, rows uint16) error { return errStub }
+func (e *GhosttyEmulator) Size() (uint16, uint16)         { return 0, 0 }
 func (e *GhosttyEmulator) PlainText() (string, error)     { return "", errStub }
 func (e *GhosttyEmulator) ScreenText() (string, error)    { return "", errStub }
 func (e *GhosttyEmulator) SerializeVT() ([]byte, error)   { return nil, errStub }