Normalize frontmatter taxonomy across 293 document transcriptions

Categories now match folder names (15 canonical values).
Types normalized to 25 canonical values per VAULT_MAP.md spec.
Context-aware mapping: W-2s→tax-form, lease files→lease, vet records→vet, etc.

documents/employment/facebook/lu_fb_offer_2020_05_08.md

@@ -1,6 +1,6 @@
 ---
-type: employment
-category: offer-letter
+type: offer-letter
+category: employment
 person: Yanxin Lu
 date: 2020-05-08
 source: lu_fb_offer_2020_05_08.pdf

documents/employment/facebook/lu_fb_offer_2020_05_13.md

@@ -1,6 +1,6 @@
 ---
-type: employment
-category: offer-letter
+type: offer-letter
+category: employment
 person: Yanxin Lu
 date: 2020-05-13
 source: lu_fb_offer_2020_05_13.pdf

documents/employment/facebook/lu_fb_offer_2020_09_21.md

@@ -1,6 +1,6 @@
 ---
-type: employment
-category: offer-letter
+type: offer-letter
+category: employment
 person: Yanxin Lu
 date: 2020-09-21
 source: lu_fb_offer_2020_09_21.pdf

documents/employment/usc/jiang_ead_2020.md

@@ -1,5 +1,5 @@
 ---
-type: immigration-document
+type: immigration
 category: employment
 person: Xuewei Jiang
 date: 2020

documents/employment/usc/jiang_i20_2020.md

@@ -1,5 +1,5 @@
 ---
-type: immigration-document
+type: immigration
 category: employment
 person: Xuewei Jiang
 date: 2020-03-11

documents/employment/usc/jiang_i94_2020.md

@@ -1,5 +1,5 @@
 ---
-type: immigration-document
+type: immigration
 category: employment
 person: Xuewei Jiang
 date: 2020-02-14

documents/employment/usc/jiang_passport_2011.md

@@ -1,5 +1,5 @@
 ---
-type: identity-document
+type: id
 category: employment
 person: Xuewei Jiang
 date: 2011-03-04

documents/employment/usc/jiang_visa_f1_2015.md

@@ -1,5 +1,5 @@
 ---
-type: immigration-document
+type: immigration
 category: employment
 person: Xuewei Jiang
 date: 2015-06-27