feat(daemon-update): render release notes as markdown + tactile Material cards

Refine the two-pane node updater:
- Release notes now render as in-app markdown (new src/ui/material/markdown.h):
  # / ## / ### headings, **bold**, `inline code` (tinted + subtle pill), and
  - / * / + bullets, word-wrapped with mixed fonts via the draw list. cleanNotes
  keeps the markdown now (only the trailing checksum table is cut), so the
  renderer styles it.
- Each version is a tactile Material card — filled rounded surface with
  hover/press/selected states (primary-tinted + outlined when selected), a
  rounded status accent bar, tag + latest/installed/pre-release badges + date —
  instead of a plain Selectable row.
- Dropped the thin 1px outlines: the version list is borderless and the notes
  sit on a filled, rounded Material surface.

The sweep's fake release body gains bold/code/multi-heading markdown to exercise
the renderer. Verified 100% + 150%, dark + light.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app_sweep.cpp

@@ -453,8 +453,17 @@ void App::buildSweepCatalog()
             };
             std::vector<util::DaemonRelease> rels;
             rels.push_back(mk("v1.0.4", "DragonX v1.0.4", "2026-06-28",
-                "## What's new\n- Faster initial block sync\n- BIP39 seed-phrase wallet support\n"
-                "- Mempool handling fixes and lower memory use\n\n## Checksums\n| File | SHA-256 |\n"
+                "## What is DragonX?\n\n"
+                "DragonX is a privacy-focused cryptocurrency built on zero-knowledge mathematics. "
+                "It enforces mandatory z2z (shielded-to-shielded) transactions after block 340,000.\n\n"
+                "## Bug Fixes\n"
+                "* Fix sapling pool persistence \xE2\x80\x94 pool total no longer resets to 0 on restart\n"
+                "* Add `subsidy` and `fees` fields to the `getblock` RPC response\n\n"
+                "## Key Features\n"
+                "* **RandomX Proof-of-Work** \xE2\x80\x94 CPU-mineable, ASIC-resistant\n"
+                "* **Sapling zk-SNARKs** \xE2\x80\x94 zero-knowledge proofs for private transactions\n"
+                "* **Encrypted P2P** \xE2\x80\x94 all connections secured with TLS 1.3 via WolfSSL\n\n"
+                "## Checksums\n| File | SHA-256 |\n"
                 "|---|---|\n| dragonx-v1.0.4-linux-amd64.zip | `ab12cd34` |\n", false));
             rels.push_back(mk("v1.0.3", "DragonX v1.0.3", "2026-05-14",
                 "## Notes\n- Stability improvements\n- RPC fixes\n", false));