feat: add bounded agenda view

Add a read-only 42-day occurrence agenda with keyboard navigation, six-week paging, exact return-to-grid focus, search and calendar overlays, and bounded recurrence expansion.

Keep agenda state outside persistence, document month-only mutations, and cover empty windows, filtering, overlays, navigation, rendering, and terminal restoration.

docs/ARCHITECTURE.md

@@ -42,10 +42,18 @@ rule cannot turn an interactive query into unbounded work.
 
 Calendar visibility is session presentation state. The controller derives its
 calendar list from event calendar identifiers and applies the same domain
-predicate to month rendering, focus traversal, and search. Hidden events remain
-in the canonical collection passed to persistence, and focus identities are
-always derived from that complete collection so filtering cannot renumber
-events with duplicate or missing UIDs.
+predicate to month rendering, agenda queries, focus traversal, and search.
+Hidden events remain in the canonical collection passed to persistence, and
+focus identities are always derived from that complete collection so filtering
+cannot renumber events with duplicate or missing UIDs.
+
+The agenda is a TUI projection over domain occurrence queries, not a second
+calendar model. It requests exactly one 42-day window at a time so recurrence
+expansion remains finite, preserves occurrence identity when returning to the
+month grid, and keeps its window and selection as non-persistent controller
+state. Calendar and search overlays may be opened above it, but mutations stay
+in the month workflow and continue to operate on the canonical event
+collection.
 
 Timed events retain their source basis: UTC, floating process-local time, or an
 IANA `TZID`. C++20 time-zone conversion keeps zoned recurrences at their civil

docs/PRODUCT.md

@@ -63,6 +63,9 @@ The full terminal is treated as a responsive canvas:
 | Next/previous appointment | `Tab` / `Shift-Tab` |
 | Read focused appointment | `Enter` |
 | Browse inside reader | arrows, `h j k l`, `Tab` / `Shift-Tab` |
+| Open/close 42-day agenda | `g`; `Esc` also closes |
+| Choose agenda occurrence | arrows, `j` / `k`, `Tab` / `Shift-Tab`, then `Enter` |
+| Shift agenda by 42 days | `PageUp` / `PageDown`, `p` / `n` |
 | Add appointment | `a` |
 | Edit focused appointment | `e` |
 | Delete focused appointment | `d`, then `y` to confirm |
@@ -77,7 +80,8 @@ The full terminal is treated as a responsive canvas:
 | Quit | `q` |
 
 The first usable foundation supports day and appointment navigation, a
-full-frame reader, validated add/edit/delete forms, and atomic `.ics` writes.
+full-frame reader, a read-only 42-day agenda, validated add/edit/delete forms,
+and atomic `.ics` writes.
 Dense days keep every appointment keyboard-reachable even when all lines do
 not fit in the cell. Unknown or unsupported iCalendar content makes a source
 read-only instead of being discarded. Saves reject external changes, retain a
@@ -88,8 +92,14 @@ semantics in the reader. `/` searches occurrence-aware title, description,
 location, and calendar-ID matches in a finite ten-year window centered on the
 selected date. `c` toggles session-only calendar visibility consistently across
 the grid, appointment focus, and search without filtering the model supplied to
-persistence. The next local-data work adds an agenda view, then advanced
-recurrence overrides and rule editing.
+persistence. `g` opens an occurrence-aware agenda at the selected month date;
+navigation is bounded to consecutive 42-day windows and `Enter` returns to the
+exact occurrence in the month grid. `Esc` or `g` closes the agenda without
+changing the month selection unless an occurrence was chosen. Hidden calendars
+remain filtered there, while calendar selection and search can overlay the
+agenda. Agenda navigation never persists state, and add/edit/delete remain in
+the month workflow. The next local-data work adds advanced recurrence overrides
+and rule editing.
 
 ## Accessibility
 

docs/ROADMAP.md

@@ -11,13 +11,14 @@
 - Windowed recurrence expansion, EXDATE, IANA TZID, and multi-day segment cues
 - Occurrence-aware appointment search with exact result-to-grid navigation
 - Session calendar toggles shared by month rendering, focus, and search
+- Read-only 42-day agenda with bounded recurrence and exact return navigation
 - Meson build, Nix development shell, desktop entry, and Hyprland launcher
 - Seeded sample data when explicitly requested, never silent data mutation
 
 ## 0.1 — complete local calendar
 
 - Advanced recurrence editing, RDATE/overrides, and embedded VTIMEZONE support
-- Agenda view, import/export, configurable week start
+- Import/export and configurable week start
 - Screen-reader-friendly linear view and full Unicode display-width handling
 
 ## 0.2 — durable cache and provider boundary