feat: add persistent dynamic panels

docs/decisions/0009-responsive-ultrawide-work-lanes.md

@@ -22,6 +22,7 @@ derives approximately 71 columns by 42 rows per panel.
 
 The runtime slice now owns three independent real PTYs through a pane-indexed
 session registry, one for every terminal fixture. The Markdown, browser, and
-review fixtures remain deterministic comparison surfaces. Adding arbitrary new
-terminal panels requires replacing the fixed fixture identity pool with dynamic
-pane creation; it does not require another runtime ownership design.
+review fixtures remain deterministic comparison surfaces. The GPUI product
+slice now adds arbitrary panels through a persistent dynamic identity layer;
+each additional Terminal panel is another entry in the same runtime ownership
+design. The fixed fixture remains only as the GPUI/Floem benchmark input.

docs/decisions/0010-panel-lifecycle-detach-before-terminate.md

@@ -15,12 +15,11 @@ confirmation that names the process, target machine, and any dirty or waiting
 state. Detaching the selected panel chooses its next attached sibling, falling
 back to the previous sibling. A workspace retains at least one attached panel.
 
-The add affordance has two product paths: quick activation creates the user's
-default panel beside the selection, while its menu offers Terminal, Browser,
-Markdown, Review, and Reattach running session. The deterministic UI spike uses
-six fixed fixtures, starts with five attached, and reattaches the first detached
-fixture when Add panel is activated. That fixture limit is test scaffolding, not
-a product limit.
+The add affordance opens a chooser for Terminal, Browser, Markdown, Review, and
+Reattach running session. The deterministic comparison model still uses six
+seed fixtures and starts with five attached. The GPUI slice no longer inherits
+that fixture limit: Add Panel creates a new persistent panel identity beside the
+selection or reattaches the exact detached identity without relaunching it.
 
 The typed command plane retains detached pane definitions separately from the
 layout tree. `ClosePane(Detach)` moves a definition into that registry,

docs/decisions/0011-dynamic-panels-have-persistent-local-identities.md

@@ -0,0 +1,23 @@
+# 0011: Dynamic panels have persistent local identities
+
+Status: accepted for the GPUI product slice.
+
+The six-surface fixture remains a deterministic benchmark shared with Floem; it
+is not the product's panel database. GPUI layers an unbounded workspace registry
+above it. Add Panel creates Terminal, Browser, Markdown, or Review beside the
+selected panel. Each new panel receives a monotonically increasing `PanelId`
+that is never derived from its title, position, surface, process ID, or visible
+index.
+
+The registry persists panel identity, kind, title, target, order, attachment,
+selection, and the next unused ID as one versioned, credential-free SQLite
+snapshot. Invalid snapshots fail closed to the seed layout rather than partially
+restoring aliases. SQLite never stores terminal output, credentials, private
+keys, subscription tokens, or Buzz identity secrets through this boundary.
+
+Every Terminal panel uses its `PanelId` as the runtime-registry key. Detaching
+changes only layout attachment, so the actor and PTY keep running. Reattaching
+selects the same ID. A restored in-process spike must currently launch a new PTY
+for that persisted panel because actor durability across UI process restarts
+requires the planned separate Lumbridge runtime and authenticated IPC; the UI
+does not pretend otherwise.