load dialog: reachable address field, project mode, and a way back from a bad answer

Three bugs, reported together, with one shared root: you couldn't get to the
address field, so the address went into the processor filter, so IDA got a
nonsense processor name and refused to open — and the app dead-ended with a
misleading error.

**Tab never reached any modal.** Binding("tab,shift+tab", "toggle_view",
priority=True) is an APP binding, and priority bindings run before the focus
chain. Nothing in any dialog in this app could ever be tabbed to; the load
dialog is just where it finally mattered. action_toggle_view now hands the key
back when a modal is up, which fixes it everywhere.

**...and DOM order was the wrong tab order anyway.** focus_next() stopped at the
processor list, which is arrow-driven and has nothing to type. LoadOptionsScreen
overrides it to cycle the two fields you actually type into.

**...and the dialog outgrew the terminal.** With the palette's default
max-height the 21-row list pushed the address field and help line off the bottom
of the screen. Nothing errors — the field simply isn't there, which reads as
"Tab does nothing". Capped per-dialog.

**Project mode never asked.** _should_ask_load_options bailed on
`self._project is not None` with the comment "project mode carries per-binary
options already" — true only if someone had already filled them in. A raw blob
added to a project got the silent x86-at-0 treatment the dialog exists to
prevent. Now asked at boot AND on switching to an undescribed binary, and the
answer is written back to the project entry (Project.set_load), so it is asked
once per binary, not once per run.

**A rejected answer dead-ended.** Getting a processor wrong is an ordinary
mistake; it left an empty app with "connect failed: worker exited (code 1)" and
a message blaming a locked .i64. The worker now names the real suspect when load
switches were in play, and the app re-opens the dialog instead of giving up.

Verified with real keys in a tmux pane, which is the only way any of this shows
up: Tab -> address field -> 0x8000000 -> Enter -> 35 functions at 0x80039AC; a
bogus processor -> "those load options were rejected — try again" with the
dialog back; project mode -> asks, loads at the right base, and the answer is in
the project file.

tests: +3 scenarios (Tab moves focus under a modal, lands on the address field,
cycles back). 202/0 scenarios, 39/0 project, 32/0 formats, 30/0 project UI.
docs/TEXTUAL_NOTES.md gets the priority-binding and clipped-modal traps.

1 files changed, 30 insertions, 0 deletions

diff --git a/docs/TEXTUAL_NOTES.md b/docs/TEXTUAL_NOTES.md
index 4bf7fcb..059b47c 100644
--- a/docs/TEXTUAL_NOTES.md
+++ b/docs/TEXTUAL_NOTES.md
@@ -80,3 +80,33 @@ Hard-won Textual behaviour and the patterns this app relies on. Pairs with
   failures. Re-run on a warm session before trusting a regression.
 - Edits mutate the `.i64` — revert renames (via API) for idempotency; use a
   PID-unique temp name to dodge collisions from a prior crashed run.
+
+
+## A priority app binding fires even under a modal
+
+`Binding("tab,shift+tab", "toggle_view", priority=True)` on the App runs before
+the focus chain, so Tab never reached ANY dialog — nothing in a modal could be
+tabbed to, in this app, ever. It looked like a bug in one dialog (the load
+options address field was unreachable) and was actually app-wide.
+
+The fix is in the action, not the binding: if a modal is up, hand the key back.
+
+```python
+def action_toggle_view(self):
+    if self.screen is not self.screen_stack[0]:
+        self.screen.focus_next()
+        return
+```
+
+Related: DOM order is rarely the tab order you want. In a dialog with a filter
+box, an option list and a second field, `focus_next()` stops at the list — which
+is arrow-driven and has nothing to type — so text meant for the second field
+lands in the filter. Override `focus_next`/`focus_previous` on the screen to
+cycle the fields people actually type into.
+
+## A modal can outgrow the terminal and clip its own controls
+
+`#pal-list { max-height: 24 }` plus a 21-row list pushed the address field and
+help line off the bottom of the screen. Nothing errors; the field is simply not
+there, which reads to the user as "Tab does nothing". Cap the scrollable part
+per-dialog so the controls below it are always visible.