feat: implement SQLite backup & data integrity plan (Phases 2-4)

app/migrations/applied/026_audit_log.sql

@@ -0,0 +1,16 @@
+-- Migration 026: create audit_log table for data-level audit trail
+-- Records before/after snapshots of every row mutation on core tables.
+-- Admin actions are already logged separately via admin_audit_log.
+CREATE TABLE IF NOT EXISTS audit_log (
+    id          INTEGER PRIMARY KEY AUTOINCREMENT,
+    timestamp   TEXT    NOT NULL DEFAULT (datetime('now')),
+    actor       TEXT    NOT NULL,
+    action      TEXT    NOT NULL CHECK(action IN ('INSERT','UPDATE','DELETE')),
+    table_name  TEXT    NOT NULL,
+    record_id   INTEGER,
+    old_data    TEXT,
+    new_data    TEXT
+);
+
+CREATE INDEX IF NOT EXISTS idx_audit_log_table_record ON audit_log(table_name, record_id);
+CREATE INDEX IF NOT EXISTS idx_audit_log_timestamp      ON audit_log(timestamp);

app/migrations/applied/027_soft_deletes.sql

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+-- Migration 027: add soft-delete columns and update views
+-- Adds deleted_at to languages, tags, theses so deletions are reversible.
+
+-- Add soft-delete columns (idempotent: ALTER TABLE ... ADD COLUMN fails gracefully if column exists)
+ALTER TABLE languages ADD COLUMN deleted_at TEXT DEFAULT NULL;
+ALTER TABLE tags      ADD COLUMN deleted_at TEXT DEFAULT NULL;
+ALTER TABLE theses    ADD COLUMN deleted_at TEXT DEFAULT NULL;
+
+-- Rebuild views to filter out soft-deleted rows.
+
+DROP VIEW IF EXISTS v_theses_public;
+DROP VIEW IF EXISTS v_theses_full;
+
+CREATE VIEW v_theses_full AS
+SELECT
+    t.id,
+    t.identifier,
+    t.title,
+    t.subtitle,
+    t.year,
+    t.is_doctoral,
+    t.objet,
+    o.name as orientation,
+    ap.name as ap_program,
+    ft.name as finality_type,
+    t.synopsis,
+    t.context_note,
+    at.name as access_type,
+    lt.name as license_type,
+    t.license_id,
+    t.license_custom,
+    t.access_type_id,
+    t.jury_points,
+    t.submitted_at,
+    t.defense_date,
+    t.published_at,
+    t.is_published,
+    t.baiu_link,
+    t.banner_path,
+    t.exemplaire_baiu,
+    t.exemplaire_erg,
+    t.cc2r,
+    t.remarks,
+    t.jury_note_added,
+    GROUP_CONCAT(DISTINCT a.name ORDER BY a.name ASC) as authors,
+    GROUP_CONCAT(DISTINCT s.name) as supervisors,
+    GROUP_CONCAT(DISTINCT CASE WHEN ts.role = 'president' THEN s.name END) as jury_president,
+    GROUP_CONCAT(DISTINCT CASE WHEN ts.role = 'promoteur' AND ts.is_ulb = 0 THEN s.name END) as jury_promoteurs,
+    GROUP_CONCAT(DISTINCT CASE WHEN ts.role = 'promoteur' AND ts.is_ulb = 1 THEN s.name END) as jury_promoteurs_ulb,
+    GROUP_CONCAT(DISTINCT CASE WHEN ts.role = 'lecteur'   AND ts.is_external = 0 THEN s.name END) as jury_lecteurs_internes,
+    GROUP_CONCAT(DISTINCT CASE WHEN ts.role = 'lecteur'   AND ts.is_external = 1 THEN s.name END) as jury_lecteurs_externes,
+    GROUP_CONCAT(DISTINCT UPPER(SUBSTR(l.name,1,1)) || SUBSTR(l.name,2)) as languages,
+    GROUP_CONCAT(DISTINCT fmt.name) as formats,
+    GROUP_CONCAT(DISTINCT tg.name) as keywords,
+    -- First author's email and contact-visibility flag
+    (SELECT a2.email        FROM authors a2 JOIN thesis_authors ta2 ON a2.id = ta2.author_id WHERE ta2.thesis_id = t.id ORDER BY ta2.author_order LIMIT 1) as contact_interne,
+    (SELECT a2.show_contact FROM authors a2 JOIN thesis_authors ta2 ON a2.id = ta2.author_id WHERE ta2.thesis_id = t.id ORDER BY ta2.author_order LIMIT 1) as contact_public
+FROM theses t
+LEFT JOIN orientations o ON t.orientation_id = o.id
+LEFT JOIN ap_programs ap ON t.ap_program_id = ap.id
+LEFT JOIN finality_types ft ON t.finality_id = ft.id
+LEFT JOIN access_types at ON t.access_type_id = at.id
+LEFT JOIN license_types lt ON t.license_id = lt.id
+LEFT JOIN thesis_authors ta ON t.id = ta.thesis_id
+LEFT JOIN authors a ON ta.author_id = a.id
+LEFT JOIN thesis_supervisors ts ON t.id = ts.thesis_id
+LEFT JOIN supervisors s ON ts.supervisor_id = s.id
+LEFT JOIN thesis_languages tl ON t.id = tl.thesis_id
+LEFT JOIN languages l ON tl.language_id = l.id AND l.deleted_at IS NULL
+LEFT JOIN thesis_formats tf ON t.id = tf.thesis_id
+LEFT JOIN format_types fmt ON tf.format_id = fmt.id
+LEFT JOIN thesis_tags tt ON t.id = tt.thesis_id
+LEFT JOIN tags tg ON tt.tag_id = tg.id AND tg.deleted_at IS NULL
+WHERE t.deleted_at IS NULL
+GROUP BY t.id;
+
+-- Published theses only (for public view)
+CREATE VIEW v_theses_public AS
+SELECT * FROM v_theses_full
+WHERE is_published = 1;