Phase 4-6: Quill editor, Lens viewer, Rigel context menu, CI, website

Phase 4 — native apps:
- quill/: text editor (monospace, double-buffered, find bar, undo, open/save)
- lens/: image viewer using imlib2 (zoom, pan, rotate, directory nav)
- wm/src/menu.c: launch quill instead of mousepad
- iso/docker/entrypoint.sh: add imlib2 package; install quill + lens binaries
- skykit/template/: developer app template demonstrating the SkyKit API

Phase 5 — file system and search:
- rigel/rigel.c: right-click context menu (open, open in quill, copy path,
  rename, trash, properties); Ctrl+F search/filter bar with name highlighting;
  F2 rename-in-place overlay; Delete key moves to trash

Phase 6 — distribution:
- .github/workflows/build-iso.yml: GitHub Actions CI that compiles all
  components and builds a bootable ISO on every tag push; creates a GitHub
  release with sha256 checksums

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

skykit/template/Makefile

@@ -0,0 +1,14 @@
+CC     = gcc
+CFLAGS = -O2 -Wall -I.. $(shell pkg-config --cflags x11 xft fontconfig)
+LIBS   = -L.. -lskykit $(shell pkg-config --libs x11 xft fontconfig)
+
+hello: hello.c ../libskykit.a
+	$(CC) $(CFLAGS) -o hello hello.c $(LIBS)
+
+../libskykit.a:
+	$(MAKE) -C ..
+
+clean:
+	rm -f hello
+
+.PHONY: clean

skykit/template/hello.c

@@ -0,0 +1,146 @@
+/* hello.c — minimal SkyKit application template
+ *
+ * Build:
+ *   cd skykit && make          (builds libskykit.a)
+ *   cd template
+ *   gcc -O2 hello.c -I.. -L.. -lskykit \
+ *       $(pkg-config --libs --cflags x11 xft fontconfig) -o hello
+ *
+ * This template shows the minimum boilerplate for a native OrionOS app:
+ *   - sk_app_init() opens the display and loads fonts
+ *   - Create a window and a Pixmap back-buffer
+ *   - Wrap them in an SKPainter
+ *   - Draw to the Pixmap, then XCopyArea to the window
+ *   - Respond to Expose, KeyPress, ButtonPress, ClientMessage
+ */
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xatom.h>
+#include <X11/keysym.h>
+#include <stdio.h>
+#include <string.h>
+#include "skykit.h"
+
+#define WIN_W 640
+#define WIN_H 400
+
+int main(void) {
+    SKApp app;
+    sk_app_init(&app);
+
+    /* ── Window ──────────────────────────────────────────── */
+    XSetWindowAttributes swa = {
+        .background_pixel = sk_color(&app, SK_BG),
+        .event_mask       = ExposureMask | KeyPressMask
+                          | ButtonPressMask | StructureNotifyMask,
+    };
+    Window win = XCreateWindow(
+        app.dpy, app.root,
+        200, 100, WIN_W, WIN_H, 0,
+        app.depth, InputOutput, app.vis,
+        CWBackPixel | CWEventMask, &swa);
+
+    /* Back-buffer for flicker-free rendering */
+    GC gc = XCreateGC(app.dpy, win, 0, NULL);
+    Pixmap buf = XCreatePixmap(app.dpy, win, WIN_W, WIN_H, app.depth);
+
+    /* SKPainter wraps the back-buffer */
+    SKPainter p = { .app = &app, .drw = buf, .gc = gc };
+
+    /* WM_DELETE_WINDOW protocol */
+    Atom wm_del = XInternAtom(app.dpy, "WM_DELETE_WINDOW", False);
+    XSetWMProtocols(app.dpy, win, &wm_del, 1);
+
+    XStoreName(app.dpy, win, "Hello OrionOS");
+    XClassHint *ch = XAllocClassHint();
+    if (ch) { ch->res_name = (char*)"hello"; ch->res_class = (char*)"Hello"; XSetClassHint(app.dpy, win, ch); XFree(ch); }
+
+    XMapWindow(app.dpy, win);
+    XFlush(app.dpy);
+
+    /* Click counter for demo */
+    int clicks = 0;
+
+    /* ── Draw function ───────────────────────────────────── */
+    /* We define a lambda-style local redraw — in a real app this would be
+     * a proper function taking your app struct. */
+    #define REDRAW() do { \
+        sk_fill(&p, SK_BG, 0, 0, WIN_W, WIN_H); \
+        \
+        /* Accent bar at top */ \
+        sk_fill(&p, SK_ACCENT, 0, 0, WIN_W, 3); \
+        \
+        /* Centred heading */ \
+        const char *title = "Hello, OrionOS"; \
+        int tw = sk_textw(&app, app.font_hdr, title); \
+        sk_text(&p, app.font_hdr, SK_TEXT_HDR, \
+                (WIN_W - tw) / 2, sk_baseline(app.font_hdr, 60, 32), title); \
+        \
+        /* Subtitle */ \
+        const char *sub = "A SkyKit native application"; \
+        int sw = sk_textw(&app, app.font_ui, sub); \
+        sk_text(&p, app.font_ui, SK_TEXT_DIM, \
+                (WIN_W - sw) / 2, sk_baseline(app.font_ui, 100, 24), sub); \
+        \
+        /* Click counter button */ \
+        SKBtn btn = { (WIN_W - 160) / 2, 160, 160, 36, "Click me", 1 }; \
+        sk_draw_btn(&p, &btn, 0); \
+        \
+        /* Counter label */ \
+        char cnt[64]; snprintf(cnt, sizeof(cnt), "Clicked %d time%s", clicks, clicks==1?"":"s"); \
+        int cw = sk_textw(&app, app.font_ui, cnt); \
+        sk_text(&p, app.font_ui, SK_TEXT, (WIN_W - cw) / 2, \
+                sk_baseline(app.font_ui, 215, 24), cnt); \
+        \
+        /* Hint */ \
+        const char *hint = "Press Q or Esc to quit"; \
+        int hw = sk_textw(&app, app.font_sm, hint); \
+        sk_text(&p, app.font_sm, SK_TEXT_DIM, (WIN_W - hw) / 2, \
+                sk_baseline(app.font_sm, WIN_H - 36, 24), hint); \
+        \
+        /* Blit to window */ \
+        XCopyArea(app.dpy, buf, win, gc, 0, 0, WIN_W, WIN_H, 0, 0); \
+        XFlush(app.dpy); \
+    } while (0)
+
+    REDRAW();
+
+    /* ── Event loop ──────────────────────────────────────── */
+    int running = 1;
+    while (running) {
+        XEvent ev;
+        XNextEvent(app.dpy, &ev);
+        switch (ev.type) {
+        case Expose:
+            if (ev.xexpose.count == 0) REDRAW();
+            break;
+        case KeyPress: {
+            KeySym ks = XLookupKeysym(&ev.xkey, 0);
+            if (ks == XK_q || ks == XK_Q || ks == XK_Escape) running = 0;
+            break;
+        }
+        case ButtonPress:
+            if (ev.xbutton.button == Button1) {
+                /* check if inside the button */
+                int bx = (WIN_W - 160) / 2, by = 160;
+                if (sk_in_rect(ev.xbutton.x, ev.xbutton.y, bx, by, 160, 36)) {
+                    clicks++;
+                    REDRAW();
+                }
+            }
+            break;
+        case ClientMessage:
+            if ((Atom)ev.xclient.data.l[0] == wm_del) running = 0;
+            break;
+        }
+    }
+
+    #undef REDRAW
+
+    sk_app_free(&app);
+    XFreePixmap(app.dpy, buf);
+    XFreeGC(app.dpy, gc);
+    XDestroyWindow(app.dpy, win);
+    XCloseDisplay(app.dpy);
+    return 0;
+}