feat: Größe ist das letzte alleinstehende (L)-Token der Zeile (D68)

Erkannt nur alleinstehend angesetzt (wie #id und :#…) — damit greifen die
Zitier-Konventionen "(L)" und ((L)) von selbst, und Backend(L) bleibt
Label. Das letzte Token gewinnt statt des ersten: Die Größe steht hinter
dem Titel, frühere Vorkommen sind Text. SPEC §1/§5 und llms.md nachgezogen;
mitgelieferte Beispiele unverändert (Parse-Vergleich alt/neu).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/public/llms.md

@@ -105,7 +105,10 @@ One node per line. Everything except the label is optional.
 
 ### Size (effort)
 
-- T-shirt sizes in parentheses: `(XS) (S) (M) (L) (XL) (XXL)`.
+- T-shirt sizes in parentheses: `(XS) (S) (M) (L) (XL) (XXL)`. Recognized
+  only **free-standing** (preceded by start-of-line or whitespace), and the
+  **last** such token of the line is the size — earlier ones stay in the
+  label. `"(L)"` and `((L))` mention a size literally (quoting convention).
 - From `(M)` upward a node **should be decomposed further**; a node ≥ M
   without children gets a placeholder hint in the diagram.
 - For cost estimation a missing size is **estimated from the sub-packages**:
@@ -134,7 +137,8 @@ One node per line. Everything except the label is optional.
    (whole line or trailing part). This also applies inside descriptions.
 2. Bare `https?://…` URL — makes the node clickable; extracted early so `@`,
    `#` and `!!!` inside URLs never trigger.
-3. `(SIZE)` — first match, case-insensitive.
+3. `(SIZE)` — the **last free-standing** match, case-insensitive; earlier
+   size-like tokens stay in the label.
 4. `@name` — people tags; several per line, any position. Characters:
    Unicode letters, digits, `.`, `_`, `-`.
 5. `#id` — **node ID**: the *first* free-standing `#token` of the line
@@ -214,7 +218,7 @@ One node per line. Everything except the label is optional.
 - Keep rejected alternatives as `[-]` instead of deleting them: the decision
   stays visible (add the reason as a `%%` comment).
 - To mention syntax literally in a label without triggering it, wrap it in
-  parentheses or quotes: `(#id)`, `(:#a,#b)`, `"#123"`.
+  parentheses or quotes: `(#id)`, `(:#a,#b)`, `"#123"`, `"(L)"`, `((L))`.
 
 ## Complete example