feat(tui): wire normal text input to LLM via A2A facade

Wires the TUI normal text input path to the LLM via A2aLocalFacade,
closing the gap where typing a message produced no LLM call. All
infrastructure (facade, SessionWorkflow, ProviderRegistry) already
existed in the CLI; this PR adds the TUI wiring on top.

Key changes:
- _run_llm_dispatch(): module-level, Textual-free dispatch function
  covering all domain exception paths with user-friendly messages
- _format_worker_outcome(): testable worker result/error translator
- _create_tui_session(): DB-backed session with persona actor binding
- _build_tui_facade(): wired A2aLocalFacade + SessionWorkflow singleton
- run_worker(thread=True, exclusive=True): non-blocking, serialised
- _dispatch_gen counter: prevents cancelled worker callbacks from
  corrupting the multi-turn transcript
- SessionView.transcript: accumulated conversation history, pre-escaped
- Markup escaping: _escape() applied before transcript storage
- on_mount focus: prompt.focus() so keyboard input is received

Tests: 18 BDD scenarios + 6 Robot Framework integration tests with
FakeListLLM (no real API keys required).

ISSUES CLOSED: #11230

robot/tui_llm_dispatch.robot

@@ -0,0 +1,82 @@
+*** Settings ***
+Documentation    Integration tests for TUI normal text input → A2A facade → LLM dispatch.
+...
+...              Verifies that:
+...              - _create_tui_session() creates a real database-backed session
+...              - _build_tui_facade() produces a wired A2aLocalFacade
+...              - CleverAgentsTuiApp dispatches normal text to the facade
+...                and renders the assistant response
+...
+...              Uses a FakeListLLM stub — no real API keys required.
+Resource         ${CURDIR}/common.resource
+Suite Setup      Setup Test Environment With Database Isolation
+Suite Teardown   Cleanup Test Environment
+
+*** Variables ***
+${HELPER}    ${CURDIR}/helper_tui_llm_dispatch.py
+
+*** Test Cases ***
+TUI Create Session Returns Real Session ID
+    [Documentation]    Verify _create_tui_session() creates a DB-backed session.
+    [Tags]    tui_llm_dispatch
+    ${result}=    Run Process    ${PYTHON}    ${HELPER}    create-session
+    ...    cwd=${WORKSPACE}
+    Log    ${result.stdout}
+    Log    ${result.stderr}
+    Should Be Equal As Integers    ${result.rc}    0
+    Should Contain    ${result.stdout}    tui-create-session-ok
+
+TUI Build Facade Returns Wired Facade
+    [Documentation]    Verify _build_tui_facade() returns a non-None A2aLocalFacade.
+    [Tags]    tui_llm_dispatch
+    ${result}=    Run Process    ${PYTHON}    ${HELPER}    build-facade
+    ...    cwd=${WORKSPACE}
+    Log    ${result.stdout}
+    Log    ${result.stderr}
+    Should Be Equal As Integers    ${result.rc}    0
+    Should Contain    ${result.stdout}    tui-build-facade-ok
+
+TUI Normal Text Dispatches To Facade And Renders Response
+    [Documentation]    Verify CleverAgentsTuiApp dispatches normal text to
+    ...                the facade and updates the conversation widget with the
+    ...                assistant response from a FakeListLLM.
+    [Tags]    tui_llm_dispatch
+    ${result}=    Run Process    ${PYTHON}    ${HELPER}    dispatch-message
+    ...    cwd=${WORKSPACE}
+    Log    ${result.stdout}
+    Log    ${result.stderr}
+    Should Be Equal As Integers    ${result.rc}    0
+    Should Contain    ${result.stdout}    tui-dispatch-message-ok
+
+TUI No Actor Error Renders Friendly Message
+    [Documentation]    Verify that when no actor is configured,
+    ...                the TUI shows a friendly error rather than crashing.
+    [Tags]    tui_llm_dispatch
+    ${result}=    Run Process    ${PYTHON}    ${HELPER}    no-actor-error
+    ...    cwd=${WORKSPACE}
+    Log    ${result.stdout}
+    Log    ${result.stderr}
+    Should Be Equal As Integers    ${result.rc}    0
+    Should Contain    ${result.stdout}    tui-no-actor-error-ok
+
+TUI DatabaseError Renders Friendly Message
+    [Documentation]    Verify _run_llm_dispatch returns a user-readable error
+    ...                string when a DatabaseError is raised during dispatch.
+    [Tags]    tui_llm_dispatch
+    ${result}=    Run Process    ${PYTHON}    ${HELPER}    database-error
+    ...    cwd=${WORKSPACE}
+    Log    ${result.stdout}
+    Log    ${result.stderr}
+    Should Be Equal As Integers    ${result.rc}    0
+    Should Contain    ${result.stdout}    tui-database-error-ok
+
+TUI SessionNotFoundError Renders Friendly Message
+    [Documentation]    Verify _run_llm_dispatch returns a user-readable error
+    ...                string when the session is missing at dispatch time.
+    [Tags]    tui_llm_dispatch
+    ${result}=    Run Process    ${PYTHON}    ${HELPER}    session-not-found
+    ...    cwd=${WORKSPACE}
+    Log    ${result.stdout}
+    Log    ${result.stderr}
+    Should Be Equal As Integers    ${result.rc}    0
+    Should Contain    ${result.stdout}    tui-session-not-found-ok