Fix REPL swallowing mid-line slashes; expose provider on CommandContext

[aronissac001-beep]

Two small changes found while building a local-inference provider on top of Clawd-Code. The first is a real bug; the second is a tiny enabling addition you may prefer to drop.

1. The REPL swallows every mid-line /

src/repl/core.py registers a key binding for / that consumes the keypress unconditionally, but only re-inserts the character when the buffer is empty:

@self.bindings.add("/")
def _show_slash_completions(event):
    buf = event.current_buffer
    if buf.text == "":          # <-- only inserts on an empty buffer
        buf.insert_text("/")
        buf.start_completion(select_first=False)

Every / typed after the first character is discarded before it reaches the buffer.

Reproduction

Type into the REPL, without submitting:

a/b/c-d/e

Screen contents, captured through a VT100 emulator (pyte) driving a real Windows pseudo-console, so prompt_toolkit runs for real:

	screen shows
main	❯ abc-de
this PR	❯ a/b/c-d/e

Why it matters more than it looks

Every file path, URL and regex typed into a prompt silently loses its separators. Asking the agent to read src/repl/core.py sends srcreplcore.py; the Read tool fails, and the agent burns turns recovering through Glob — when it recovers at all. In one of my runs it took three tool calls to find a file it had been handed the exact path to.

The failure mode is easy to misattribute: it looks like the model is hallucinating paths, because by the time anything is logged the slashes are already gone. It is invisible to any test that does not go through a real terminal — I only found it after driving the REPL through a genuine pty, having earlier "verified" the REPL by calling handle_command()/chat() directly, which bypasses prompt_toolkit entirely.

The fix

Always insert the character; open the command palette only when / is the first character on the line, which is what the binding was for. /help and the palette still behave as before.

2. Expose the active provider on CommandContext

CommandContext carries the conversation, cost tracker and history, but not the provider, so a local command cannot inspect or reconfigure the model it is talking to. Commands that report or switch model state have no supported route to it.

Adds an optional provider field, threads it through create_command_context, and passes it from the REPL. Defaulted to None, so every existing caller is unaffected.

This one is a small enabling change rather than a bug fix, and it has no consumer in this PR — the commands that use it live in my fork. It is a separate commit, so please drop it if you would rather it arrived with its callers. The first commit stands alone.

Testing

• A/B verified in a real terminal via pywinpty + pyte, shown above.
• /help and the slash palette still open correctly.
• Read src/local/router.py resolves on the first attempt instead of the third.
• Both commits compile; change is 3 files, +14/−2.